Device for calculating a received quality of reference signal

ABSTRACT

[Object] To make it possible to select a cell that is more preferable for a terminal device in an environment in which beamforming is performed. 
     [Solution] There is provided a device including: an acquiring unit configured to acquire first received power information indicating received power of a reference signal for measurement transmitted by a target base station using a weight set for beamforming in a terminal device and second received power information indicating received power of a reference signal for measurement transmitted by another base station using a weight set for beamforming in the terminal device; and a control unit configured to calculate received quality of the reference signal transmitted by the target base station in the terminal device based on the first received power information and the second received power information.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/307,866, filed Oct. 31, 2016, which is based on PCT filingPCT/JP2015/062146, filed Apr. 21, 2015, which claims priority to JP2014-111655, filed May 29, 2014, the entire contents of each areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a device.

BACKGROUND ART

Currently, in the Third Generation Partnership Project (3GPP), in orderto accommodate explosively increasing traffic, various technologies forincreasing the capacity of cellular systems are being investigated. Inthe future, it is predicted that a capacity of about 1000 times thecurrent capacity will be necessary. Technologies such as multi-usermultiple-input multiple-output (MU-MIMO) and coordinated multipoint(CoMP) are considered to increase the capacity of cellular systems toonly about several times the previous capacity. Therefore, abreakthrough technique is necessary.

For example, as a technique for significantly increasing the capacity ofcellular systems, a base station that uses a directional antennaincluding multiple antenna elements (for example, about 100 antennaelements) and performs beamforming is considered. Such technology is aform of technology called large-scale MIMO or massive MIMO. According tosuch beamforming, a half width of a beam is narrowed. That is, a sharpbeam is formed. In addition, when the multiple antenna elements arearranged on a plane, it is also possible to form a beam in a desiredthree-dimensional direction.

Various beamforming technologies are proposed. For example, in PatentLiterature 1, technology for implementing beamforming by a base stationeven when frequency bands of an upstream channel and a downstreamchannel are different is disclosed.

CITATION LIST Patent Literature

Patent Literature 1 JP 2011-004056A

SUMMARY OF INVENTION Technical Problem

However, when beamforming is performed, received quality of a referencesignal (for example, reference signal received quality (RSRQ)) may besignificantly varied. For example, interference from another basestation may be significantly varied according to which weight set isused for the other base station to perform beamforming. Therefore, forexample, a received signal strength indicator (RSSI) significantlyvaries and RSRQ also significantly varies. Specifically, when thebeamforming is large-scale MIMO or massive MIMO beamforming, there is apossibility of RSRQ being significantly greatly varied. As a result, forexample, a cell that is not preferable as a cell in which a terminaldevice performs wireless communication (for example, a target cell of ahandover) may be selected.

Therefore, it is preferable to provide a mechanism through which it ispossible to select a cell that is more preferable for a terminal devicein an environment in which beamforming is performed.

Solution to Problem

According to the present disclosure, there is provided a deviceincluding: an acquiring unit configured to acquire first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in a terminal device and second received power informationindicating received power of a reference signal for measurementtransmitted by another base station using a weight set for beamformingin the terminal device; and a control unit configured to calculatereceived quality of the reference signal transmitted by the target basestation in the terminal device based on the first received powerinformation and the second received power information.

According to the present disclosure, there is provided a deviceincluding: an acquiring unit configured to acquire first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in a terminal device and second received power informationindicating received power of a signal transmitted within a symbol inwhich physical downlink control channels are arranged in the terminaldevice; and a control unit configured to calculate received quality ofthe reference signal transmitted by the target base station in theterminal device using the first received power information and thesecond received power information.

According to the present disclosure, there is provided a deviceincluding: an acquiring unit configured to acquire received powerinformation indicating received power of a reference signal formeasurement transmitted by a base station using a weight set forbeamforming in a terminal device; and a control unit configured toprovide the received power information to a base station.

Advantageous Effects of Invention

According to the present disclosure described above, it is possible toselect a cell that is more preferable for a terminal device in anenvironment in which beamforming is performed. Note that the effectsdescribed above are not necessarily limitative. With or in the place ofthe above effects, there may be achieved any one of the effectsdescribed in this specification or other effects that may be graspedfrom this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for describing a weight set forlarge-scale MIMO beamforming.

FIG. 2 is an explanatory diagram for describing a relation betweenmultiplication of a weight coefficient and insertion of a referencesignal.

FIG. 3 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to an embodiment ofthe present disclosure.

FIG. 4 is a first explanatory diagram for describing an example oflarge-scale MIMO beamforming.

FIG. 5 is a second explanatory diagram for describing an example oflarge-scale MIMO beamforming.

FIG. 6 is an explanatory diagram for describing a first example oftransmission of reference signals for measurement multiplied bydifferent weight sets.

FIG. 7 is an explanatory diagram for describing a first example oftransmission of reference signals for measurement by different basestations.

FIG. 8 is an explanatory diagram for describing a second example oftransmission of reference signals for measurement by different basestations.

FIG. 9 is an explanatory diagram for describing a second example oftransmission of reference signals for measurement multiplied bydifferent weight sets.

FIG. 10 is an explanatory diagram for describing multiplication of areference signal for measurement by a weight coefficient.

FIG. 11 is a block diagram illustrating an example of a configuration ofa terminal device according to a first embodiment.

FIG. 12 is a flowchart illustrating an example of a schematic flow of aprocess according to the first embodiment.

FIG. 13 is a block diagram illustrating an example of a configuration ofa terminal device according to a second embodiment.

FIG. 14 is a block diagram illustrating an example of a configuration ofa base station according to a second embodiment.

FIG. 15 is a sequence diagram illustrating an example of a schematicflow of a process according to the second embodiment.

FIG. 16 is a block diagram illustrating an example of a configuration ofa terminal device according to a third embodiment.

FIG. 17 is a flowchart illustrating an example of a schematic flow of aprocess according to the third embodiment.

FIG. 18 is a block diagram illustrating an example of a configuration ofa terminal device according to a fourth embodiment.

FIG. 19 is a block diagram illustrating an example of a configuration ofa base station according to the fourth embodiment.

FIG. 20 is a sequence diagram illustrating an example of a schematicflow of a process according to the fourth embodiment.

FIG. 21 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 22 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 23 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 24 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

DESCRIPTION OF EMBODIMENT(S)

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the drawings, elements that have substantially thesame function and structure are denoted with the same reference signs,and repeated explanation is omitted.

In this specification and the drawings, there are cases in whichcomponents having substantially the same functional configuration aredistinguished by adding different alphabets to the end of the samereference numeral. For example, a plurality of components havingsubstantially the same functional configuration are distinguished liketerminal devices 100A, 100B, and 100C as necessary. However, when aplurality of components having substantially the same functionalconfiguration need not be particularly distinguished, only the samereference numeral is added. For example, when the terminal devices 100A,100B, and 100C need not be particularly distinguished, they are referredto simply as a “terminal devices 100.”

The description will proceed in the following order.

1. Introduction

2. Schematic configuration of communication system

3. Transmission of reference signal

4. Common points and different points of first to fourth embodiments

5. First Embodiment

5.1. Configuration of terminal device

5.2. Method of calculating received quality

5.3. Process flow

6. Second Embodiment

6.1. Configuration of terminal device

6.2. Configuration of base station

6.3. Method of calculating received quality

6.4. Process flow

7. Third Embodiment

7.1. Configuration of terminal device

7.2. Method of calculating received quality

7.3. Process flow

8. Fourth Embodiment

8.1. Configuration of terminal device

8.2. Configuration of base station

8.3. Method of calculating received quality

8.4. Process flow

9. Application examples

9.1. Application examples for base station

9.2. Application examples for terminal device

10. Conclusion

1. Introduction

First, beamforming, measurement and cell selection will be describedwith reference to FIG. 1 and FIG. 2.

(Beamforming)

(a) Necessity of Large-Scale MIMO

Currently, in the 3GPP, in order to accommodate explosively increasingtraffic, various technologies for increasing the capacity of cellularsystems are being investigated. In the future, it is predicted that acapacity of about 1000 times the current capacity will be necessary.Technologies such as MU-MIMO and CoMP are considered to increase thecapacity of cellular systems to only about several times the previouscapacity. Therefore, a breakthrough technique is necessary.

In 3GPP release 10, an eNodeB in which eight antennas are implemented isstandardized. According to the antennas, eight-layer MIMO can beimplemented in single-user multiple-input multiple-output (SU-MIMO).8-layer MIMO is technology in which eight independent streams arespatially multiplexed. In addition, it is possible to implementtwo-layer MU-MIMO with four users.

In user equipment (UE), it is difficult to increase the number ofantenna elements of an antenna of the UE due to a small space forarranging antennas and a limited UE processing capacity. However,according to recent advances in antenna mounting technology, it ispossible to arrange a directional antenna including about 100 antennaelements in an eNodeB.

For example, as a technique for significantly increasing the capacity ofcellular systems, a base station that uses a directional antennaincluding multiple antenna elements (for example, about 100 antennaelements) and performs beamforming is considered. Such technology is aform of technology called large-scale MIMO or massive MIMO. According tosuch beamforming, a half width of a beam is narrowed. That is, a sharpbeam is formed. In addition, when the multiple antenna elements arearranged on a plane, it is also possible to form a beam in a desiredthree-dimensional direction. For example, a technique is proposed inwhich a beam directed toward a position higher than a base station (forexample, an upper floor of a high-rise building) is formed, and thus asignal is transmitted to a terminal device in such a position.

In typical beamforming, it is possible to change a direction of a beamin a horizontal direction. Therefore, the typical beamforming may bereferred to as two-dimensional beamforming. On the other hand, inlarge-scale MIMO (or massive MIMO) beamforming, it is possible to changea direction of a beam in a vertical direction in addition to thehorizontal direction. Therefore, the large-scale MIMO beamforming may bereferred to as three-dimensional beamforming.

Since the number of antennas increases, it is possible to increase thenumber of users of MU-MIMO. Such technology is another form oftechnology called large-scale MIMO or massive MIMO. When the number ofantennas of a UE is 2, the number of streams that are spatiallyindependent in a single UE is 2. Therefore, increasing the number ofusers of MU-MIMO is more reasonable than increasing the number ofstreams in a single UE.

(b) Weight Set

A weight set for beamforming (that is, a set of weight coefficients formultiple antenna elements) is represented as a complex number.Hereinafter, an example of a weight set for large-scale MIMO beamformingwill be described specifically with reference to FIG. 1.

FIG. 1 is an explanatory diagram for describing a weight set forlarge-scale MIMO beamforming. Referring to FIG. 1, antenna elementsarranged in a grid pattern are shown. In addition, two orthogonal axes xand y on a plane in which antenna elements are arranged and one axis zorthogonal to the plane are shown. Here, a direction of a beam to beformed is indicated by, for example, an angle phi (a Greek letter) andan angle theta (a Greek letter). The angle phi (a Greek letter) is anangle formed by a component of an xy plane within a beam direction andthe x axis. In addition, the angle theta (a Greek letter) is an angleformed by a beam direction and the z axis. In this case, for example, aweight coefficient V_(m,n) of an antenna element that is arranged at anm-th point in an x axis direction and arranged at an n-th point in a yaxis direction may be represented as follows.

$\begin{matrix}{{V_{m,n}\left( {\theta,\varphi,f} \right)} = {\exp\left( {j\; 2\;\pi\frac{f}{c}\left\{ {{\left( {m - 1} \right)d_{x}{\sin(\theta)}{\cos(\varphi)}} + {\left( {n - 1} \right)d_{y}{\sin(\theta)}{\sin(\varphi)}}} \right\}} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 1} \right\rbrack\end{matrix}$

f denotes a frequency and c denotes the speed of light. j denotes animaginary unit of a complex number. d_(x) denotes an interval betweenantenna elements in the x axis direction. d_(y) denotes an intervalbetween antenna elements in the y axis direction. Coordinates of theantenna element are represented as follows.x=(m−1)d _(x) , y=(n−1)d _(y)  [Math. 2]

A weight set for typical beamforming (two-dimensional beamforming) maybe decomposed into a weight set for forming a beam in a desiredhorizontal direction and a weight set for adjusting transfer betweenantennas. Therefore, a weight set for large-scale MIMO beamforming maybe decomposed into a first weight set for forming a beam in a desiredvertical direction, a second weight set for forming a beam in a desiredhorizontal direction and a third weight set for adjusting transferbetween antennas.

(c) Change of Environment According to Large-Scale MIMO Beamforming

When large-scale MIMO beamforming is performed, a gain reaches 10 dB ormore. A change of a radio wave environment of a cellular system usingthe beamforming may be greater than a cellular system of the relatedart.

(d) Case in which Large-Scale MIMO Beamforming is Performed

For example, a base station of an urban area forming a beam directedtoward a high-rise building is considered. In addition, even in asuburb, a base station of a small cell is considered to form a beamdirected toward an area around the base station. A base station of asuburban macro cell is unlikely to perform large-scale MIMO beamforming.

(Measurement)

(a) CRS Measurement

In Long Term Evolution (LTE), a terminal device performs measurement ofa cell-specific reference signal (CRS) transmitted by a base station.Specifically, the terminal device receives a CRS transmitted by a basestation and thus performs measurement of quality of a propagation pathbetween the base station and the terminal device. The measurement isreferred to as “radio resource management (RRM) measurement,” or issimply referred to as “measurement.”

A result of the measurement is used to select a cell for a terminaldevice. As a specific example, the result of the measurement is used forcell selection/cell reselection by a terminal device that is in a radioresource control (RRC) idle (RRC Idle) state. In addition, for example,the result of the measurement is reported to a base station by aterminal device that is in an RRC connected state and is used for ahandover decision by the base station.

As described above, measurement is performed by receiving a CRS. Sincethe CRS is a signal for measuring quality of a transmission path ofomnidirectional radio waves, it is transmitted without beamforming. Thatis, the CRS is transmitted without multiplying the weight set forbeamforming.

There is a reference signal for demodulation called a demodulationreference signal (DM-RS) or a UE-specific reference signal. Since thereference signal for demodulation is multiplied by the weight set forbeamforming, it is not preferable to measure quality of a transmissionpath of omnidirectional radio waves. In addition, there is a referencesignal called a channel state information reference signal (CSI-RS).Similarly to the CRS, the CSI-RS is transmitted without beamforming.However, since a transmission frequency of the CSI-RS is low,measurement by receiving the CSI-RS consumes much time. Hereinafter, arelation between multiplication of a weight coefficient and insertion(or mapping) of a reference signal will be described with reference toFIG. 2.

FIG. 2 is an explanatory diagram for describing a relation betweenmultiplication of a weight coefficient and insertion of a referencesignal. Referring to FIG. 2, a transmission signal 92 corresponding toeach antenna element 91 is complex-multiplied by a weight coefficient 93in a multiplier 94. Then, the transmission signal 92 complex-multipliedby the weight coefficient 93 is transmitted from the antenna element 91.In addition, a DR-MS 95 is inserted before the multiplier 94, and theweight coefficient 93 is complex-multiplied in the multiplier 94. Then,the DR-MS 95 complex-multiplied by the weight coefficient 93 istransmitted from the antenna element 91. On the other hand, a CRS 96(and CSI-RS) is inserted after the multiplier 94. Then, the CRS 96 (andCSI-RS) is transmitted from the antenna element 91 without beingmultiplied by the weight coefficient 93.

(b) RSRP and RSRQ

In LTE, CRS measurement is measurement of reference signal receivedpower (RSRP) and/or reference signal received quality (RSRQ). In otherwords, a terminal device acquires RSRP and/or RSRQ as a result of themeasurement of the CRS. The RSRQ is calculated from the RSRP and areceived signal strength indicator (RSSI).

The RSRP is received power of a CRS for each single resource element.That is, the RSRP is an average value of received power of the CRS. Thereceived power of the CRS is obtained by detecting a correlation betweena reception signal in a resource element of the CRS and a known signalCRS. The RSRP corresponds to a desired signal “Signal (S).”

The RSSI is total power of signals for each Orthogonal FrequencyDivision Multiple Access (OFDMA) symbol. Therefore, the RSSI includes adesired signal, an interference signal and noise. That is, the RSSIcorresponds to “Signal (S)+Interference (I)+Noise (N).”

The RSRQ is RSRP/(RSSI/N). N denotes the number of resource blocks usedfor calculating an RSSI. The resource blocks are resource blocks thatare arranged in a frequency direction. Therefore, the RSRQ is a valuethat is obtained by dividing the RSRP using the RSSI for each resourceblock. That is, the RSRQ corresponds to asignal-to-interference-plus-noise ratio (SINR).

As described above, according to the measurement of the CRS, receivedpower (that is, RSRP) and received quality (that is, RSRQ) such as anSINR are obtained.

(c) Effect of Averaging

In order to acquire the RSRP and the RSRQ, it is necessary to receivesignals for several milliseconds to several tens of milliseconds andperform averaging of received power thereof. This is because, a resultis likely to be influenced by an instantaneous variation of a channelsuch as fading when the RSRP and the RSRQ are acquired by averaging onlyone slot or one subset.

A technique of averaging is implemented for each terminal device and isnot specifically defined in the specification.

(Cell selection)

(a) Example of Cell Selection

For example, when a terminal device is in an RRC idle state, cellselection/cell reselection is performed. That is, the terminal deviceselects a cell for performing communication (for example, a cell forreceiving paging).

In addition, for example, a base station performs a handover decision.That is, the base station selects a target cell for the terminal deviceand decides whether a handover from a serving cell for the terminaldevice to the target cell is performed.

In addition, for example, the base station adds a secondary cell (Scell)of carrier aggregation. The Scell is also called a secondary componentcarrier (SCC).

Here, the term “cell” may refer to a communication area of the basestation or a frequency band that the base station uses. In addition, theterm “cell” may refer to a primary cell (Pcell) or an Scell of carrieraggregation. The Pcell is also called a primary component carrier (PCC).The Scell is also called a secondary component carrier (SCC).

(b) Cell Selection when Beamforming is Performed

As described above, in the form of the technology called large-scaleMIMO or massive MIMO, the base station performs beamforming using adirectional antenna including multiple antenna elements (for example,about 100 antenna elements). In this case, the base station can change adirection of a beam in not only the horizontal direction but also thevertical direction. Therefore, as an example, when the base stationforms a beam directed toward a position (for example, an upper floor ofa high-rise building) higher than the base station, it is possible toincrease throughput at the high position. As another example, when asmall base station forms a beam toward a nearby area, it is possible toreduce interference with an adjacent base station.

Here, when transmission and reception of signals according tolarge-scale MIMO beamforming become a main flow, there is a question ofwhether cell selection may be performed based on the result ofmeasurement of the CRS.

Specifically, only quality of a transmission path of omnidirectionalradio waves can be understood from measurement of the CRS. However, thetransmission path of omnidirectional radio waves is completely differentfrom a transmission path of a sharp beam that is formed according tolarge-scale MIMO beamforming. Therefore, when transmission and receptionof signals according to the beamforming are assumed, there is apossibility of an appropriate cell not being selected in cell selectionbased on the result of measurement of the CRS.

As an example, when a terminal device transmits and receives signals ina cell selected based on the result of measurement of the CRS, there isa possibility of a great amount of interference due to a sharp beam froman adjacent base station. As another example, even if a result ofmeasurement of a CRS of a certain cell is more favorable than a resultof measurement of a CRS of another cell, there is a possibility ofcommunication quality of the other cell being more favorable thancommunication quality of the certain cell when beamforming is performed.

As described above, there is a possibility of an appropriate cell for aterminal device not being selected when beamforming is performed.

(c) Case in which Measurement of a CRS is not Preferable

As described above, for example, large-scale MIMO beamforming isconsidered to be performed by a base station of an urban area or a basestation of a small cell. Therefore, it is not preferable for such basestations to perform cell selection based on measurement of a CRS.

2. Schematic Configuration of Communication System

Next, a schematic configuration of a communication system 1 according toan embodiment of the present disclosure will be described with referenceto FIGS. 3 to 5. FIG. 3 is an explanatory diagram illustrating anexample of the schematic configuration of the communication system 1according to the embodiment of the present disclosure. Referring to FIG.3, the communication system 1 includes a terminal device 100 and a basestation 200. The communication system 1 is a system supporting, forexample, LTE, LTE-Advanced, or a communication standard equivalentthereto.

(Terminal Device 100)

The terminal device 100 wirelessly communicates with a base station. Forexample, when the terminal device 100 is positioned within acommunication area of the base station 200, the terminal device 100wirelessly communicates with the base station 200.

(Base Station 200)

The base station 200 wirelessly communicates with a terminal device. Forexample, the base station 200 wirelessly communicates with a terminaldevice that is positioned within a communication area of the basestation 200 (including, for example, the terminal device 200).

(Environment in which Beamforming is Performed)

Specifically, in embodiments of the present disclosure, beamforming isperformed by a base station (for example, including the base station200). For example, beamforming is performed by a base station that ispositioned around the terminal device 100. For example, the beamformingis large-scale MIMO beamforming. The beamforming may also be referred toas massive MIMO beamforming or three-dimensional beamforming.

As a specific example, the base station (for example, the base station200) includes a directional antenna capable of large-scale MIMO. Inaddition, the base station multiplies a transmission signal by a weightset for the directional antenna and thus performs large-scale MIMObeamforming. For example, the weight set is decided for each terminaldevice (for example, the terminal device 100). As a result, a beamdirected toward the terminal device is formed. Hereinafter, an exampleof large-scale MIMO beamforming will be described with reference to FIG.4 and FIG. 5.

FIG. 4 is a first explanatory diagram for describing an example oflarge-scale MIMO beamforming. Referring to FIG. 4, a directional antenna201 available for large-scale MIMO is shown. The directional antenna 201can form a sharp beam in a desired three-dimensional direction. Forexample, a beam 21A and a beam 21B are formed by the directional antenna201.

FIG. 5 is a secondary explanatory diagram for describing an example oflarge-scale MIMO beamforming. Referring to FIG. 5, the beams 21A and 21Bdescribed with reference to FIG. 4 are shown. For example, the beam 21Areaches an area 23A and the beam 21B reaches an area 23B. Therefore, aterminal device 100A positioned within the area 23A can receive a signaltransmitted as the beam 21A. In addition, a terminal device 100Bpositioned within the area 23B can receive a signal transmitted as thebeam 21B. The base station 200 transmits a signal addressed to theterminal device 100A as the beam 21A and transmits a signal addressed tothe terminal device 100B as the beam 21B.

The base station (for example, the base station 200) can transmit, forexample, a signal without beamforming. As an example, the base stationincludes an omnidirectional antenna and transmits a signal asomnidirectional radio waves. As another example, the base stationincludes a sector antenna and may transmit a signal as a sector beam.

3. Transmission of Reference Signal

Next, an example of transmission of a reference signal in an embodimentof the present disclosure will be described with reference to FIG. 6 toFIG. 10.

Specifically, in an embodiment of the present disclosure, a base station(for example, the base station 200) transmits a reference signal formeasurement using a weight set for beamforming. That is, the basestation multiplies the reference signal by the weight set and transmitsthe reference signal multiplied by the weight set. As a result, thereference signal is transmitted as a beam.

Accordingly, for example, it is possible to measure actual receivedpower in an environment in which beamforming is performed.

(Beamforming)

For example, the beamforming is large-scale MIMO beamforming. In otherwords, the beamforming may also be referred to as massive MIMObeamforming or three-dimensional beamforming.

The beamforming may be an existing type of beamforming (for example,two-dimensional beamforming).

(Reference Signal for Measurement)

For example, the reference signal (that is, the reference signal formeasurement) is a reference signal specific to a cell. For example, abase station transmits the reference signal in addition to thecell-specific reference signal (CRS). That is, the reference signal is asignal different from the CRS. The reference signal may include the samesignal sequence as the CRS or a different signal sequence from that ofthe CRS.

The reference signal may be the CRS. In this case, the CRS may bemultiplied by the weight set.

Specific Example

(a) First RS Transmission Case

In a first case (hereinafter referred to as a “first RS transmissioncase”), a base station uses different radio resources in order totransmit reference signals for measurement multiplied by differentweight sets. Hereinafter, this will be described with reference to aspecific example of FIG. 6.

FIG. 6 is an explanatory diagram for describing a first example oftransmission of reference signals for measurement multiplied bydifferent weight sets. As illustrated in FIG. 6, two resource blocksarranged in a time direction within a subframe 30 are shown. In thisexample, the subframe 30 includes 14 OFDMA symbols. A control area 31 ofthe subframe 30 includes the 1st to 3rd

OFDMA symbols. A data area 33 of the subframe 30 includes the 4th to14th OFDMA symbols. In this example, a base station of a cell Xtransmits a reference signal for measurement multiplied by a weight setV(i) (i=0 to 3) using resource elements associated with the weight setV(i). In this manner, in the first RS transmission case, referencesignals for measurement multiplied by different weight sets aretransmitted using different radio resources.

In addition, for example, different base stations (for example,different base stations that are positioned around the terminal device100) use different radio resources in order to transmit referencesignals for measurement multiplied by a weight set. Hereinafter, thiswill be described with reference to a specific example of FIG. 7 andFIG. 8.

FIG. 7 is an explanatory diagram for describing a first example oftransmission of reference signals for measurement by different basestations. As illustrated in FIG. 7, pairs 40 of resource blocks of thesubframe 30 are shown. The pairs 40 are arranged in a frequencydirection. In addition, each of the pairs 40 includes two resourceblocks that are arranged in the time direction. In this example, a basestation of a cell 0 transmits a reference signal for measurementmultiplied by a weight set using radio resources included in pairs 40Aand 40E of resource blocks. A base station of a cell 1 transmits areference signal for measurement multiplied by a weight set using radioresources included in pairs 40B and 40F of resource blocks. A basestation of a cell 2 transmits a reference signal for measurementmultiplied by a weight set using radio resources included in pairs 40Cand 40G of resource blocks. A base station of a cell 3 transmits areference signal for measurement multiplied by a weight set using radioresources included in pairs 40D and 40H of resource blocks. In thismanner, different base stations use different radio resources in orderto transmit reference signals for measurement multiplied by a weightset.

FIG. 8 is an explanatory diagram for describing a second example oftransmission of reference signals for measurement by different basestations. As illustrated in FIG. 8, a radio frame including 10 subframesis shown. In this example, a base station of a cell 0 transmits areference signal for measurement multiplied by a weight set using radioresources of subframes whose subframe numbers are 0 and 5. A basestation of a cell 1 transmits a reference signal for measurementmultiplied by a weight set using radio resources of subframes whosesubframe numbers are 1 and 6. A base station of a cell 2 transmits areference signal for measurement multiplied by a weight set using radioresources of subframes whose subframe numbers are 2 and 7. A basestation of a cell 3 transmits a reference signal for measurementmultiplied by a weight set using radio resources of subframes whosesubframe numbers are 3 and 8. In this manner, different base stationsuse different radio resources in order to transmit reference signals formeasurement multiplied by a weight set.

For example, as described above, in the first RS transmission case, thebase station uses different radio resources in order to transmitreference signals for measurement multiplied by different weight sets. Ause pattern of radio resources described with reference to FIG. 6 toFIG. 8 is only an example, and various patterns may be applied to anembodiment of the present disclosure.

(b) Second RS Transmission Case

In a second case (hereinafter referred to as a “second RS transmissioncase”), a base station transmits reference signals for measurementmultiplied by different weight sets using the same radio resources. Thatis, the base station transmits reference signals for measurementmultiplied by different weight sets through spatial multiplexing.Hereinafter, this will be described with reference to a specific exampleof FIG. 9.

FIG. 9 is an explanatory diagram for describing a second example oftransmission of reference signals for measurement multiplied bydifferent weight sets. As illustrated in FIG. 9, similarly to FIG. 6,two resource blocks arranged in the time direction within the subframe30 are shown. In this example, a base station of a cell X transmits areference signal for measurement multiplied by a weight set V(i) (i=0 to3) using resource elements common to a weight set V. In this manner, inthe second RS transmission case, reference signals for measurementmultiplied by different weight sets are transmitted using the same radioresources.

In addition, for example, different base stations (for example,different base stations that are positioned around the terminal device100) use different radio resources in order to transmit referencesignals for measurement multiplied by a weight set. This is the same aswhat is described in the first RS transmission case with reference toFIG. 7 and FIG. 8.

For example, as described above, in the second RS transmission case, thebase station uses the same radio resources in order to transmitreference signals for measurement multiplied by different weight sets. Ause pattern of radio resources described with reference to FIG. 7 toFIG. 9 is only an example, and various patterns may be applied to anembodiment of the present disclosure.

(Multiplication of Weight Coefficient)

A weight set is a set of weight coefficients for a plurality of antennaelements and a reference signal for measurement is multiplied by aweight coefficient corresponding to an antenna element for each of theantenna elements. Hereinafter, this will be described with reference toa specific example of FIG. 10.

FIG. 10 is an explanatory diagram for describing multiplication of areference signal for measurement by a weight coefficient. As illustratedin FIG. 10, a transmission signal 73 corresponding to each antennaelement 71 is complex-multiplied by a weight coefficient 75 in amultiplier 77. Then, the transmission signal 73 complex-multiplied bythe weight coefficient 75 is transmitted from the antenna element 71. Inaddition, a reference signal for measurement 79 is inserted (that is, ismapped to radio resources) before the multiplier 77, and the weightcoefficient 75 is complex-multiplied in the multiplier 77. Then, thereference signal for measurement 79 complex-multiplied by the weightcoefficient 75 is transmitted from the antenna element 71.

4. Common Points and Different Points of First to Fourth Embodiments

Next, common points and different points of first to fourth embodimentsof the present disclosure will be described.

(Common Points)

In the first to fourth embodiments of the present disclosure, receivedquality of a reference for measurement transmitted by a target basestation using a weight set for beamforming in the terminal device 100 iscalculated based on first received power information and second receivedpower information. The first received power information is informationindicating received power of the reference signal transmitted by thetarget base station using the weight set in the terminal device 100.

(Different Points)

(a) Different Points Between First and Second Embodiments and Third andFourth Embodiments

In the first embodiment and the second embodiment of the presentdisclosure, the second received power information is informationindicating received power of a reference signal for measurementtransmitted by another base station using a weight set for beamformingin the terminal device 100.

In the third embodiment and the fourth embodiment of the presentdisclosure, the second received power information is informationindicating received power of a signal transmitted within a symbol inwhich physical downlink control channels are arranged in the terminaldevice 100.

(b) Different Points Between First Embodiment and Second Embodiment

In the first embodiment, the terminal device 100 calculates the receivedquality based on the first received power information and the secondreceived power information.

In the second embodiment, the base station 200 calculates the receivedquality based on the first received power information and the secondreceived power information. The terminal device 100 provides receivedpower information indicating received power of a reference signal formeasurement transmitted by a base station using a weight set forbeamforming to the base station 200 in the terminal device 100.

(c) Different points between third embodiment and fourth embodiment

In the third embodiment, the terminal device 100 calculates the receivedquality based on the first received power information and the secondreceived power information.

In the fourth embodiment, the base station 200 calculates the receivedquality based on the first received power information and the secondreceived power information. The terminal device 100 provides receivedpower information indicating received power of a reference signal formeasurement transmitted by a base station using a weight set forbeamforming to the base station 200 in the terminal device 100.

5. First Embodiment

Next, a first embodiment of the present disclosure will be describedwith reference to FIG. 11 and FIG. 12.

<5.1. Configuration of Terminal Device>

First, an example of a configuration of the terminal device 100-1according to the first embodiment will be described with reference toFIG. 11. FIG. 11 is a block diagram illustrating an example of aconfiguration of the terminal device 100-1 according to the firstembodiment. As illustrated in FIG. 11, the terminal device 100-1includes an antenna unit 110, a wireless communication unit 120, astorage unit 130 and a processing unit 140.

(Antenna Unit 110)

The antenna unit 110 emits a signal output by the wireless communicationunit 120 into space as radio waves. In addition, the antenna unit 110converts spatial radio waves into a signal, and outputs the signal tothe wireless communication unit 120.

(Wireless Communication Unit 120)

The wireless communication unit 120 transmits and receives signals. Forexample, the wireless communication unit 120 receives a downlink signalfrom the base station 200-1 and transmits an uplink signal to the basestation 200-1.

(Storage Unit 130)

The storage unit 130 stores programs and data for operations of theterminal device 100-1.

(Processing Unit 140)

The processing unit 140 provides various functions of the terminaldevice 100-1. The processing unit 140 includes a measurement unit 141,an information acquiring unit 143 and a control unit 145. Alternatively,the processing unit 140 may further include a component other than thesecomponents. That is, the processing unit 140 may also perform anoperation other than operations of these components.

(Measurement Unit 141)

The measurement unit 141 measures received power of a reference signalfor measurement transmitted by a base station using a weight set forbeamforming in the terminal device 100-1. For example, the measurementunit 141 outputs received power information indicating the receivedpower.

(a) Measurement in RS Transmission Cases

(a-1) First RS Transmission Case

As described above, in the first RS transmission case, the base stationuses different radio resources in order to transmit reference signalsfor measurement multiplied by different weight sets.

In this case, for example, for each of two or more weight sets, themeasurement unit 141 measures received power of a reference signal formeasurement transmitted by a base station using a weight set in theterminal device 100-1. More specifically, for example, the measurementunit 141 measures received power of a reference signal for measurementthat is transmitted using radio resources associated with a weight setin the terminal device 100-1 for each of two or more weight sets. Then,the measurement unit 141 outputs received power information of each ofthe two or more weight sets.

Referring again to FIG. 6, for example, the measurement unit 141measures received power of a reference signal transmitted using a weightset V(0), received power of a reference signal transmitted using aweight set V(1), received power of a reference signal transmitted usinga weight set V(2), and received power of a reference signal transmittedusing a weight set V(3). Then, the measurement unit 141 outputs receivedpower information of the weight set V(0), received power information ofthe weight set V(1), received power information of the weight set V(2)and received power information of the weight set V(3).

Even in the first RS transmission case, similarly to the second RStransmission case to be described, the terminal device 100-1 can measurereceived power. As an example, a total sum of received powers for allweight sets Vs is calculated and thus received power may be measuredsimilarly to the second RS transmission case to be described.

(a-2) Second RS Transmission Case

As described above, in the second RS transmission case, the base stationuses the same radio resources in order to transmit reference signals formeasurement multiplied by different weight sets. That is, the basestation transmits reference signals for measurement multiplied bydifferent weight sets through spatial multiplexing.

In this case, for example, the measurement unit 141 measures receivedpower of a reference signal for measurement transmitted by a basestation using a weight set in the terminal device 100-1. Morespecifically, for example, the measurement unit 141 measures receivedpower of a reference signal for measurement that is transmitted usingradio resources common to weight sets in the terminal device 100-1.Then, the measurement unit 141 outputs received power information commonto weight sets.

Referring again to FIG. 9, for example, the measurement unit 141measures received power of a reference signal transmitted using a weightset V. That is, the measurement unit 141 measures received power of areference signal for measurement that is transmitted using radioresources common to weight sets V(i) (i=0, 1, 2, 3) in the terminaldevice 100-1. Then, the measurement unit 141 outputs received powerinformation common to the weight sets V(i).

(b) Measurement for Each Base Station

For example, for each of a plurality of base stations, the measurementunit 141 measures received power of a reference signal for measurementtransmitted by a base station using a weight set in the terminal device100-1.

More specifically, for example, for each of the plurality of basestations, the measurement unit 141 measures received power of areference signal for measurement that is transmitted using radioresources associated with the base station in the terminal device 100-1.For example, the plurality of base stations are base stations that arepositioned around the terminal device 100-1. Then, the measurement unit141 outputs received power information for each of the plurality of basestations.

Referring again to FIG. 7 and FIG. 8, for example, the measurement unit141 measures received power of a reference signal transmitted by thebase station of the cell 0, received power of a reference signaltransmitted by the base station of the cell 1, received power of areference signal transmitted by the base station of the cell 2, andreceived power of a reference signal transmitted by the base station ofthe cell 3. Then, the measurement unit 141 outputs received powerinformation for the base station of the cell 0, received powerinformation for the base station of the cell 1, received powerinformation for the base station of the cell 2, and received powerinformation for the base station of the cell 3.

A described above, there is a case in which different radio resourcesare used in order to transmit reference signals for measurementmultiplied by different weight sets (that is, the first RS transmissioncase). In this case, for example, the measurement unit 141 measuresreceived power of a reference signal for measurement transmitted by abase station using a weight set for each of the plurality of basestations in the terminal device 100-1 for each of two or more weightsets.

Referring again to FIG. 6 to FIG. 8, for example, for the base stationof the cell 0, the measurement unit 141 measures received power of areference signal that is transmitted using the weight set V(0), receivedpower of a reference signal that is transmitted using the weight setV(1), received power of a reference signal that is transmitted using theweight set V(2), and received power of a reference signal that istransmitted using the weight set V(3). Then, for the base station of thecell 0, the measurement unit 141 outputs received power information ofthe weight set V(0), received power information of the weight set V(1),received power information of the weight set V(2) and received powerinformation of the weight set V(3).

Similarly to the base station of the cell 0, the base station of thecell 1, the base station of the cell 2 and the base station of the cell3 also measure received power of a reference signal that is transmittedusing each of the weight sets V(0), V(1), V(2), and V(3) and outputreceived power information of each of the weight sets V(0), V(1), V(2),and V(3).

(c) Learning about Radio Resources

For example, the base station 200-1 notifies the terminal device 100-1of radio resources that are used to transmit a reference signal formeasurement multiplied by a weight set. In this case, the measurementunit 141 measures received power of a reference signal for measurementthat is transmitted using the radio resources of which the base station200-1 notifies the terminal device 100-1.

As described above, the radio resources used to transmit a referencesignal for measurement multiplied by a weight set may be predefinedradio resources. In this case, information for specifying the radioresources may be stored in the storage unit 130. Then, the measurementunit 141 may measure received power of a reference signal formeasurement that is transmitted using the radio resources (that is, thepredefined radio resources) specified from the information stored in thestorage unit 130.

(d) Specific Process

As described above, the measurement unit 141 measures received power ofa reference signal for measurement transmitted by a base station using aweight set in the terminal device 100-1. For example, the measurementunit 141 measures received power of the reference signal for each unitresource. More specifically, for example, the measurement unit 141measures received power of the reference signal for each resourceelement. That is, the measurement unit 141 performs a process ofaveraging received power.

Received power to be measured is not limited to the above-describedexample. As an example, the measurement unit 141 may measure a total sumof received powers of the reference signals.

(Information Acquiring Unit 143)

The information acquiring unit 143 acquires received power informationindicating received power of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in theterminal device 100-1.

For example, the received power information is output by the measurementunit 141. The information acquiring unit 143 acquires the received powerinformation.

(a) First Received Power Information

The information acquiring unit 143 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-1.

The target base station is a base station serving as a target whosereceived quality will be calculated. That is, the target base station ischanged according to a base station whose received quality will becalculated. As an example, the processing unit 140 (for example, thecontrol unit 145) selects the target base station from among a pluralityof base stations that are positioned around the terminal device 100-1.

(b) Second Received Power Information

The information acquiring unit 143 acquires second received powerinformation indicating received power of a reference signal formeasurement transmitted by another base station using a weight set forbeamforming in the terminal device 100-1. Second received powerinformation that will be acquired by the information acquiring unit 143will be described below in detail along with a method of calculatingreceived quality.

The other base station is a base station that is different from a basestation serving as a target whose received quality will be calculated.That is, the other base station may also be changed according to thebase station whose received quality will be calculated.

When the terminal device 100-1 wirelessly communicates with the targetbase station, the other base station serves as an interference source ofthe terminal device 100-1 and the target base station. Therefore, itshould be noted that the second received power information indicatesinterference power.

(Control Unit 145)

(a) Calculation of Received Quality

The control unit 145 calculates received quality of the reference signaltransmitted by the target base station in the terminal device 100-1based on the first received power information and the second receivedpower information. The method of calculating received quality will bedescribed below in detail.

(b) Provision to base station

For example, the control unit 145 provides the first received powerinformation to the base station 200-1.

For example, the control unit 145 provides received quality informationindicating the calculated received quality to the base station 200-1.

Specifically, for example, the control unit 145 provides the firstreceived power information and the received quality information to thebase station 200-1 periodically and/or according to a generation of apredetermined event. The control unit 145 provides the first receivedpower information and the received quality information to the basestation 200-1 through the antenna unit 110 and the wirelesscommunication unit 120.

<5.2. Method of Calculating Received Quality>

Next, an example of the method of calculating received quality in thefirst embodiment will be described.

(Assumed Expression)

(a) Base Station

A base station is represented by “B.” Further, a target base station isrepresented by “B(0).” Another base station is represented by “B(x)”(x=1, 2, 3, (b) Weight set

A weight set is represented by “V” Specifically, an individual weightset is represented by “V(i)” (i=1, 2, 3, . . . ).

(c) Received Power of Reference Signal for Measurement

Received power of a reference signal for measurement in the terminaldevice 100-1 is represented by “RSRP.”

(c-1) First RS Transmission Case

As described above, in the first RS transmission case (that is, in acase in which reference signals for measurement multiplied by differentweight sets are transmitted using different radio resources), theterminal device 100-1 can measure received power for each weight setV(i). Therefore, for example, in the first RS transmission case,received power of a reference signal for measurement transmitted by thetarget base station B(0) using the weight set V(i) in the terminaldevice 100-1 is represented as follows.RSRP(B(0) with V(i))  [Math. 3]

In addition, for example, in the first RS transmission case, receivedpower of a reference signal for measurement transmitted by another basestation B(x) using a weight set V(j) in the terminal device 100-1 isrepresented as follows.RSRP(B(x) with V(j))  [Math. 4]

As described above, even in the first RS transmission case, the terminaldevice 100-1 can measure received power similarly to the second RStransmission case.

(c-2) Second RS Transmission Case

As described above, in the second RS transmission case (that is, a casein which reference signals for measurement multiplied by differentweight sets are transmitted using the same radio resources), receivedpower common to the weight set V is measured. Therefore, for example, inthe second case, received power of a reference signal for measurementtransmitted by the target base station B(0) using the weight set V inthe terminal device 100-1 is represented as follows.RSRP(B(0) with V)  [Math. 5]

Similarly, received power of a reference signal for measurementtransmitted by another base station B(x) using the weight set V in theterminal device 100-1 is represented as follows.RSRP(B(x) with V)  [Math. 6](d) Received Quality of Reference Signal for Measurement

Received quality of a reference signal for measurement in the terminaldevice 100-1 is represented by “RSRQ.”

(d-1) First RS Transmission Case

For example, in the first RS transmission case, for example, the secondreceived power information indicates received power of a referencesignal for measurement transmitted by the other base station B(x) usingthe weight set V(j) in the terminal device 100-1. Then, received qualityof a reference signal for measurement transmitted by the target basestation B(0) using the weight set V(i) in the terminal device 100-1 iscalculated based on the second received power information. In this case,the received quality is represented as follows.RSRQ(B(0) with V(i),B(x) with V(j))  [Math. 7]

Even in the first RS transmission case, the terminal device 100-1 cancalculate received quality similarly to the second RS transmission case.

(d-2) Second RS Transmission Case

For example, in the second RS transmission case, for example, the secondreceived power information indicates received power of a referencesignal for measurement transmitted by the other base station B(x) usingthe weight set V in the terminal device 100-1. Then, received quality ofa reference signal for measurement transmitted by the target basestation B(0) using the weight set V in the terminal device 100-1 iscalculated based on the second received power information.

In this case, the received quality is represented as follows.RSRQ(B(0) with V,B(x) with V)  [Math. 8](Received Quality in First RS Transmission Case)

First, in the first RS transmission case in which reference signals formeasurement multiplied by different weight sets are transmitted usingdifferent radio resources, an example of the method of calculatingreceived quality of a reference for measurement transmitted by thetarget base station B(0) using the weight set V(i) in the terminaldevice 100-1 will be described.

The control unit 145 calculates the received quality based on the firstreceived power information and the second received power information.

The first received power information indicates received power of areference signal for measurement transmitted by the target base stationB(0) using the weight set V(i) in a terminal device. As described above,the received power is represented as follows.RSRP(B(0) with V(i))  [Math. 9](a) Another Base Station and One Weight Set(a-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the firstreceived power information and the second received power information ofone weight set for another base station.

As an example, the information acquiring unit 143 acquires the secondreceived power information of another weight set V(n) for another basestation B(a). Received power indicated by the second received powerinformation is represented as follows.

TABLE 1 Another Second received power base station Weight setinformation (received power) B(a) V(n) RSRP (B(a) with V(n))(a-2) Calculation of Received Quality

As an example, the control unit 145 calculates the received quality byperforming division using received power indicated by the first receivedpower information and received power indicated by the second receivedpower information. Specifically, for example, the control unit 145calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}},{{B(a)}\mspace{14mu}{with}\mspace{14mu}{V(n)}}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)}{{RSRP}\left( {{B(a)}\mspace{14mu}{with}\mspace{14mu}{V(n)}} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 10} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) uses the weight set V(i) and the other base station B(a)uses the weight set V(n). That is, in this method, the other basestation B(a) that uses the weight set V(n) is considered to be aninterference source.

In this method, the other base station B(a) that uses a weight set V(j)other than the weight set V(n) and a base station B(x) other than theother base station B(a) are not considered to be interference sources.

(a-3) Weight Set

Received Power

For example, the weight set used by the other base station is a weightset that provides higher received power in the terminal device 100-1than other weight sets. Specifically, for example, the weight set V(n)used by the other base station B(a) provides higher received power thanthe other weight sets among weight sets V(j) (j=0, 1, 2, 3, . . . ).Accordingly, for example, when received quality is calculated, a higherinterference source is considered. That is, for example, receivedquality when interference is high is calculated.

Designation

The weight set used by the other base station may be a designated weightset. Specifically, the weight set used by the other base station may bea weight set that is designated by a network (for example, the basestation 200-1 or a core network node). Accordingly, for example, when aweight set that is used by a base station in the network is determinedor when a weight set that is used by the base station can be adjusted,it is possible to calculate received quality with high accuracy.

(b) Plurality of Other Base Stations

(b-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the secondreceived power information for each of a plurality of other basestations. For example, the plurality of other base stations are basestations that are positioned around the terminal device 100-1.

For example, the information acquiring unit 143 acquires the firstreceived power information and the second received power information ofone weight set for each of the plurality of other base stations.

As an example, the information acquiring unit 143 acquires the secondreceived power information of one weight set V(n_(x)) for each of threeother base stations B(x) (x=1, 2, 3). That is, the information acquiringunit 143 acquires second received power information of a weight setV(n₁) for another base station B(1), second received power informationof a weight set V(n₂) for another base station B(2), and second receivedpower information of a weight set V(n₃) for another base station B(3).Received power indicated by such second received power information isrepresented as follows.

TABLE 2 Other base Second received power stations Weight setsinformation (received power) B(1) V(n₁) RSRP (B(1) with V(n₁)) B(2)V(n₂) RSRP (B(2) with V(n₂)) B(3) V(n₃) RSRP (B(3) with V(n₃))

Weight sets used by other base stations may be different among theplurality of other base stations. Any two of the weight set V(n₁), theweight set V(n₂) and the weight set V(n₃) may be different from eachother.

(b-2) Calculation of Received Quality

For example, the control unit 145 calculates the received quality basedon the first received power information and the second received powerinformation for each of the plurality of other base stations.

Specifically, for example, the control unit 145 calculates the receivedquality based on first received power indicated by the first receivedpower information and second received power calculated based on thesecond received power information for each of the plurality of otherbase stations. For example, the second received power is a sum ofreceived powers indicated by the second received power information. Asan example, the second received power is represented as follows.

$\begin{matrix}{\sum\limits_{x = 1}^{3}\;{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x} \right)}} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 11} \right\rbrack\end{matrix}$

More specifically, for example, the control unit 145 calculates thereceived quality by performing division using the first received powerand the second received power. Specifically, for example, the controlunit 145 calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}},{{B(x)}_{x = {1\mspace{11mu}{to}\mspace{11mu} 3}}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x} \right)}}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)}{\sum\limits_{x = 1}^{3}\;{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x} \right)}} \right)}}} & \left\lbrack {{Math}.\mspace{14mu} 12} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) uses the weight set V(i) and other base stations B(x) (x=1,2, 3) use the weight set V(n_(x)). That is, in this method, the otherbase stations B(x) (x=1, 2, 3) that use the weight set V(n_(x)) areconsidered to be interference sources.

In this method, the other base stations B(x) (x=1, 2, 3) that use aweight set V(j) other than the weight set V(n_(x)) are not considered tobe interference sources.

For example, as described above, the control unit 145 calculates thereceived quality based on the first received power information and thesecond received power information for each of the plurality of otherbase stations. Accordingly, for example, more accurate received qualityis calculated in consideration of interference from the plurality ofother base stations that are positioned around the terminal device100-1. As a result, a cell that is more preferable for the terminaldevice 100-1 may be selected.

(b-3) Weight Set

Received Power

For example, the weight set used by the other base station is a weightset that provides higher received power in the terminal device 100-1than other weight sets. Specifically, for example, the weight setV(n_(x)) used by the other base stations B(x) provides higher receivedpower than the other weight sets among weight sets V(j) (j=0, 1, 2, 3, .. . ). Accordingly, for example, a higher interference source isconsidered when received quality is calculated. That is, for example,received quality when interference is high is calculated.

Designation

The weight set used by the other base station may be a designated weightset. Specifically, the weight set used by the other base station may bea weight set that is designated by a network (for example, the basestation 200-1 or a core network node). Accordingly, for example, when aweight set that is used by a base station in the network is determinedor when a weight set that is used by the base station can be adjusted,it is possible to calculate received quality with high accuracy.

(c) Two or More Weight Sets

(c-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the secondreceived power information of each of two or more weight sets.

For example, the information acquiring unit 143 acquires the firstreceived power information and the second received power information oftwo or more weight sets for another base station.

As an example, the information acquiring unit 143 acquires the secondreceived power information of four weight sets V(j) (j=0, 1, 2, 3) foranother base station B(a). That is, the information acquiring unit 143acquires second received power information of the weight set V(0) forthe other base station B(a), second received power information of theweight set V(1) for the other base station B(a), second received powerinformation of the weight set V(2) for the other base station B(a), andsecond received power information of the weight set V(3) for the otherbase station B(a). Received power indicated by such second receivedpower information is represented as follows.

TABLE 3 Other base Second received power stations Weight setsinformation (received power) B(a) V(0) RSRP(B(a) with v(0)) B(a) V(1)RSRP(B(a) with V(1)) B(a) V(2) RSRP(B(a) with V(2)) B(a) V(3) RSRP(B(a)with V(3))(c-2) Calculation of Received Quality

For example, the control unit 145 calculates the received quality basedon the first received power information and the second received powerinformation of each of the two or more weight sets.

Specifically, for example, the control unit 145 calculates the receivedquality based on first received power indicated by the first receivedpower information and second received power calculated based on thesecond received power information of each of the two or more weightsets. For example, the second received power is a sum of received powersindicated by the second received power information. As an example, thesecond received power is represented as follows.

$\begin{matrix}{\sum\limits_{j = 0}^{3}\;{{RSRP}\left( {{B(a)}\mspace{14mu}{with}\mspace{14mu}{V(j)}} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 13} \right\rbrack\end{matrix}$

More specifically, for example, the control unit 145 calculates thereceived quality by performing division using the first received powerand the second received power. Specifically, for example, the controlunit 145 calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}},{{B(a)}\mspace{14mu}{with}\mspace{14mu}{V(j)}_{j = {0\mspace{11mu}{to}\mspace{11mu} 3}}}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)}{\sum\limits_{j = 0}^{3}\;{{RSRP}\left( {{B(a)}\mspace{14mu}{with}\mspace{14mu}{V(j)}} \right)}}} & \left\lbrack {{Math}.\mspace{14mu} 14} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) uses the weight set V(i) and the other base station B(a)uses the weight set V(j) (j=0, 1, 2, 3). That is, in this method, theother base station B(a) that uses the weight set V(j) (j=0, 1, 2, 3) isconsidered to be an interference source.

In this method, the base station B(x) other than the other base stationB(a) is not considered to be an interference source.

For example, as described above, the control unit 145 calculates thereceived quality based on the first received power information and thesecond received power information of each of the two or more weightsets. Accordingly, more accurate received quality is calculated inconsideration of interference from other base stations that use the twoor more weight sets. As a result, a cell that is more preferable for theterminal device 100-1 may be selected.

(c-3) Weight Set

Received Power

For example, the two or more weight sets are weight sets that providehigher received power in the terminal device 100-1 than other weightsets. Specifically, for example, the weight sets V(0), V(1), V(2), andV(3) used by the other base station B(a) provide higher received powerthan the other weight sets among weight sets V(j) (j=0, 1, 2, 3, 4, . .. ). Accordingly, for example, a higher interference source isconsidered when received quality is calculated. That is, for example,received quality when interference is high is calculated.

Designation

The two or more weight sets may be designated weight sets. Specifically,the two or more weight sets may be weight sets that are designated by anetwork (for example, the base station 200-1 or a core network node).Accordingly, for example, when a weight set that is used by a basestation in the network is determined or when a weight set that is usedby the base station can be adjusted, it is possible to calculatereceived quality with high accuracy.

(d) Plurality of Other Base Stations and Two or More Weight Sets

(d-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the secondreceived power information of each of two or more weight sets for eachof a plurality of other base stations. For example, the plurality ofother base stations are base stations that are positioned around theterminal device 100-1.

As an example, the information acquiring unit 143 acquires the secondreceived power information of four weight sets V(n_(xk)) (k=0, 1, 2, 3)for three other base stations B(x) (x=1, 2, 3). That is, the informationacquiring unit 143 acquires second received power information of aweight set V(n₁₀) for another base station B(1), second received powerinformation of a weight set V(n₁₁) for the other base station B(1),second received power information of a weight set V(n₁₂) for the otherbase station B(1), and second received power information of a weight setV(n₁₃) for the other base station B(1). The information acquiring unit143 acquires second received power information for each weight set forother base stations B(2) and B(3) similarly to the other base stationB(1). Received power indicated by such second received power informationis represented as follows.

TABLE 4 Other base Second received power stations Weight setsinformation (received power) B(1) V(n₁₀) RSRP(B(1) with V(n₁₀)) B(1)V(n₁₁) RSRP(B(1) with V(n₁₁)) B(1) V(n₁₂) RSRP(B(1) with V(n₁₂)) B(1)V(n₁₃) RSRP(B(1) with V(n₁₃)) B(2) V(n₂₀) RSRP(B(2) with V(n₂₀)) B(2)V(n₂₁) RSRP(B(2) with V(n₂₁)) B(2) V(n₂₂) RSRP(B(2) with V(n₂₂)) B(2)V(n₂₃) RSRP(B(2) with V(n₂₃)) B(3) V(n₃₀) RSRP(B(3) with V(n₃₀)) B(3)V(n₃₁) RSRP(B(3) with V(n₃₁)) B(3) V(n₃₂) RSRP(B(3) with V(n₃₂)) B(3)V(n₃₃) RSRP(B(3) with V(n₃₃))

The two or more weight sets may be different among the plurality ofother base stations. Any two of a weight set V(n_(1k)) (k=0, 1, 2, 3,4), a weight set V(n_(2k)) (k=0, 1, 2, 3, 4), and a weight set V(n_(3k))(k=0, 1, 2, 3, 4) may be different from each other.

(d-2) Calculation of Received Quality

For example, the control unit 145 calculates the received quality basedon the first received power information and the second received powerinformation of each of the two or more weight sets for each of theplurality of other base stations.

Specifically, for example, the control unit 145 calculates the receivedquality based on first received power indicated by the first receivedpower information and second received power calculated based on thesecond received power information of each of the two or more weight setsfor each of the plurality of other base stations. For example, thesecond received power is a sum of received powers indicated by thesecond received power information. As an example, the second receivedpower is represented as follows.

$\begin{matrix}{\sum\limits_{x = 1}^{3}\;{\sum\limits_{k = 0}^{3}{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x\; k} \right)}} \right)}}} & \left\lbrack {{Math}.\mspace{14mu} 15} \right\rbrack\end{matrix}$

More specifically, for example, the control unit 145 calculates thereceived quality by performing division using the first received powerand the second received power. Specifically, for example, the controlunit 145 calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}},{{B(x)}_{x = {1\mspace{14mu}{to}\mspace{11mu} 3}}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x\; k} \right)}_{k = {0\mspace{11mu}{to}\mspace{11mu} 3}}}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)}{\sum\limits_{x = 1}^{3}\;{\sum\limits_{k = 0}^{3}{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu}{V\left( n_{x\; k} \right)}} \right)}}}} & \left\lbrack {{Math}.\mspace{14mu} 16} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) uses the weight set V(i) and other base stations B(x) (x=1,2, 3) use the weight set V(n_(xk)) (k=0, 1, 2, 3). That is, in thismethod, the other base stations B(x) (x=1, 2, 3) that use the weight setV(n) (k=0, 1, 2, 3) are considered to be interference sources.

For example, as described above, the control unit 145 calculates thereceived quality based on the first received power information and thesecond received power information of each of the two or more weight setsfor each of the plurality of other base stations. Accordingly, moreaccurate received quality is calculated in consideration of interferencefrom the plurality of other base stations that use two or more weightsets. As a result, a cell that is more preferable for the terminaldevice 100-1 may be selected.

(d-3) Weight Set

Received Power

For example, the two or more weight sets are weight sets that providehigher received power in the terminal device 100-1 than other weightsets. Specifically, for example, the weight set V(n) (k=0, 1, 2, 3) usedby the other base station B(x) provides higher received power than theother weight sets among weight sets V(j) (j=0, 1, 2, 3, . . . ).Accordingly, for example, a higher interference source is consideredwhen received quality is calculated. That is, for example, receivedquality when interference is high is calculated.

Designation

The two or more weight sets may be designated weight sets. Specifically,the two or more weight sets may be weight sets that are designated by anetwork (for example, the base station 200-1 or a core network node).Accordingly, for example, when a weight set that is used by a basestation in the network is determined or when a weight set that is usedby the base station can be adjusted, it is possible to calculatereceived quality with high accuracy.

The method of calculating received quality in the first RS transmissioncase has been described above. Even in the first RS transmission case itis possible to calculate received quality similarly to the second RStransmission case to be described. As an example, when received powerinformation indicating a total sum of received powers for all weightsets V is used, received quality may be calculated similarly to thesecond RS transmission case to be described.

(Received Quality in Second RS Transmission Case)

Next, in the second RS transmission case in which reference signals formeasurement multiplied by different weight sets are transmitted usingthe same radio resources, an example of the method of calculatingreceived quality of a reference for measurement transmitted by thetarget base station B(0) using the weight set V in the terminal device100-1 will be described.

The control unit 145 calculates the received quality based on the firstreceived power information and the second received power information.

The first received power information indicates received power of areference signal for measurement transmitted by the target base stationB(0) using the weight set V in a terminal device. As described above,the received power is represented as follows.RSRP(B(0) with V)  [Math. 17](a) Another Base Station(a-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the firstreceived power information and the second received power information foranother base station.

As an example, the information acquiring unit 143 acquires the secondreceived power information for another base station B(a). Received powerindicated by the second received power information is represented asfollows.

TABLE 5 Another base Second received power station information (receivedpower) B(a) RSRP(B(a) with V)(a-2) Calculation of Received Quality

As an example, the control unit 145 calculates the received quality byperforming division using received power indicated by the first receivedpower information and the received power indicated by the secondreceived power information. Specifically, for example, the control unit145 calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu} V},{{B(a)}\mspace{14mu}{with}\mspace{14mu} V}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu} V} \right)}{{RSRP}\left( {{B(a)}\mspace{14mu}{with}\mspace{14mu} V} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 18} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) and the other base station B(a) use the weight set V. Thatis, in this method, the other base station B(a) that uses the weight setV is considered to be an interference source.

In this method, the base station B(x) other than the other base stationB(a) is not considered to be an interference source.

(b) Plurality of Other Base Stations

(b-1) Second Received Power Information

For example, the information acquiring unit 143 acquires the secondreceived power information for each of a plurality of other basestations. For example, the plurality of other base stations are basestations that are positioned around the terminal device 100-1.

As an example, the information acquiring unit 143 acquires the secondreceived power information for each of three other base stations B(x)(x=1, 2, 3). That is, the information acquiring unit 143 acquires secondreceived power information for the base station B(1), second receivedpower information for the base station B(2), and second received powerinformation for the base station B(3). Received power indicated by suchsecond received power information is represented as follows.

TABLE 6 Other base Second received power stations information (receivedpower) B(1) RSRP(B(1) with V) B(2) RSRP(B(2) with V) B(3) RSRP(B(3) withV)(b-2) Calculation of Received Quality

For example, the control unit 145 calculates the received quality basedon the first received power information and the second received powerinformation for each of the plurality of other base stations

Specifically, for example, the control unit 145 calculates the receivedquality based on first received power indicated by the first receivedpower information and second received power calculated based on thesecond received power information for each of the plurality of otherbase stations. For example, the second received power is a sum ofreceived powers indicated by the second received power information. Asan example, the second received power is represented as follows.

$\begin{matrix}{\sum\limits_{x = 1}^{3}\;{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu} V} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 19} \right\rbrack\end{matrix}$

More specifically, for example, the control unit 145 calculates thereceived quality by performing division using the first received powerand the second received power. Specifically, for example, the controlunit 145 calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{{B(0)}\mspace{14mu}{with}\mspace{14mu} V},{{B(x)}_{x = {1\mspace{11mu}{to}\mspace{11mu} 3}}\mspace{14mu}{with}\mspace{14mu} V}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu} V} \right)}{\sum\limits_{x = 1}^{3}\;{{RSRP}\left( {{B(x)}\mspace{14mu}{with}\mspace{14mu} V} \right)}}} & \left\lbrack {{Math}.\mspace{14mu} 20} \right\rbrack\end{matrix}$

It should be noted that the received quality calculated by this methodis received quality in the target base station B(0) when the target basestation B(0) and other base stations B(x) (x=1, 2, 3) use the weight setV. That is, in this method, the other base stations B(x) (x=1, 2, 3)that use the weight set V are considered to be interference sources.

For example, as described above, the control unit 145 calculates thereceived quality based on the first received power information and thesecond received power information for each of the plurality of otherbase stations. Accordingly, for example, more accurate received qualityis calculated in consideration of interference from the plurality ofother base stations that are positioned around the terminal device100-1. As a result, a cell that is more preferable for the terminaldevice 100-1 may be selected.

(Target Base Station)

(a) Target Base Station

As described above, the target base station is a base station serving asa target whose received quality will be calculated. For example, theprocessing unit 140 (for example, the control unit 145) selects thetarget base station from among the plurality of base stations that arepositioned around the terminal device 100-1. As an example, theprocessing unit 140 selects a base station of a measurement target cell(for example, a serving cell and a neighbor cell) as the target basestation. As a result, received quality in the selected base station iscalculated.

It should be understood that not only one target base station but alsotwo or more target base stations may be selected. As a result, receivedquality in each of the two or more target base stations may becalculated.

(b) Weight Set Used by Target Base Station

As described above, in the first RS transmission case, the receivedquality can be calculated for each weight set used by the target basestation. For example, the processing unit 140 (for example, the controlunit 145) selects a weight set from among a plurality of weight setsused by the target base station. As a result, received quality for theselected weight set is calculated.

It should be understood that not only one weight set but also two ormore weight sets may be selected. As a result, received quality for eachof the two or more weight sets may be calculated.

<5.3. Process Flow>

Next, an example of a process according to the first embodiment will bedescribed with reference to FIG. 12. FIG. 12 is a flowchart illustratingan example of a schematic flow of a process according to the firstembodiment. The process is performed by the terminal device 100-1.

The information acquiring unit 143 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-1 (S301).

In addition, the information acquiring unit 143 acquires second receivedpower information indicating received power of a reference signal formeasurement transmitted by another base station using a weight set forbeamforming in the terminal device 100-1 (S303).

Then, the control unit 145 calculates received quality of the referencesignal transmitted by the target base station in the terminal device100-1 based on the first received power information and the secondreceived power information (S305). Then, the process ends.

The first embodiment has been described above. According to the firstembodiment, for example, it is possible to select a cell that is morepreferable for the terminal device 100-1 in an environment in whichbeamforming is performed. More specifically, for example, receivedquality in the target base station is calculated based on received power(that is, received power indicated by first received power information)in the target base station and interference (that is, received powerindicated by second received power information) in the environment inwhich beamforming is performed. Therefore, the received quality may beclose to received quality when the terminal device 100-1 performswireless communication in the environment in which beamforming isperformed. Then, the received quality is used when a handover or a cellselection/cell reselection is performed. As a result, a cell that ismore preferable for the terminal device 100-1 may be selected.

In addition, since the terminal device 100-1 calculates the receivedquality in the first embodiment, information for calculating thereceived quality may not be transmitted to the base station 200-1.Therefore, radio resources may be saved.

6. Second Embodiment

Next, the second embodiment of the present disclosure will be describedwith reference to FIG. 13 to FIG. 15.

While the terminal device 100-1 calculates received quality in the firstembodiment, a base station 200-2 calculates received quality in thesecond embodiment.

<6.1. Configuration of Terminal Device>

First, an example of a configuration of a terminal device 100-2according to the second embodiment will be described with reference toFIG. 13. FIG. 13 is a block diagram illustrating an example of aconfiguration of the terminal device 100-2 according to the secondembodiment. As illustrated in FIG. 13, the terminal device 100-2includes the antenna unit 110, the wireless communication unit 120, thestorage unit 130 and a processing unit 150.

There is no difference in descriptions of the antenna unit 110, thewireless communication unit 120 and the storage unit 130 between thefirst embodiment and the second embodiment except for differentreference numerals. Therefore, redundant descriptions will be omittedhere, and only the processing unit 150 will be described.

(Processing Unit 150)

The processing unit 150 provides various functions of the terminaldevice 100-2. The processing unit 150 includes the measurement unit 141,an information acquiring unit 153, and a control unit 155.Alternatively, the processing unit 150 may further include a componentother than these components. That is, the processing unit 150 mayperform an operation other than operations of these components.

There is no difference in descriptions of the measurement unit 141between the first embodiment and the second embodiment except fordifferent reference numerals. Therefore, redundant descriptions will beomitted here, and only the information acquiring unit 153 and thecontrol unit 155 will be described.

(Information Acquiring Unit 153)

The information acquiring unit 153 acquires received power informationindicating received power of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in theterminal device 100-2.

For example, the received power information is output by the measurementunit 141. The information acquiring unit 153 acquires the received powerinformation.

For example, the received power information is a candidate for firstreceived power information and second received power information usedfor calculating received quality.

(Control Unit 155)

The control unit 155 provides the received power information to the basestation 200-2.

Specifically, for example, the control unit 155 provides the receivedpower information to the base station 200-2 periodically and/oraccording to a generation of a predetermined event. The control unit 155provides the received power information to the base station 200-2through the antenna unit 110 and the wireless communication unit 120.

<6.2. Configuration of Base Station>

Next, an example of a configuration of the base station 200-2 accordingto the second embodiment will be described with reference to FIG. 14.FIG. 14 is a block diagram illustrating an example of a configuration ofthe base station 200-2 according to the second embodiment. Asillustrated in FIG. 14, the base station 200-2 includes the antenna unit210, the wireless communication unit 220, the network communication unit230, the storage unit 240 and a processing unit 260.

(Antenna Unit 210)

The antenna unit 210 emits a signal to be output by the wirelesscommunication unit 220 into space as radio waves. In addition, theantenna unit 210 converts spatial radio waves into a signal and outputsthe signal to the wireless communication unit 220.

For example, the antenna unit 210 includes a directional antenna. Forexample, the directional antenna is a directional antenna capable oflarge-scale MIMO.

In addition, for example, the antenna unit 210 further includes anomnidirectional antenna. Alternatively, the antenna unit 210 may includea sector antenna with or without an omnidirectional antenna.

(Wireless Communication Unit 220)

The wireless communication unit 220 transmits and receives signals. Forexample, the wireless communication unit 220 transmits a downlink signalto the terminal device 100-2 and receives an uplink signal from theterminal device 100-2.

(Network Communication Unit 230)

The network communication unit 230 transmits and receives information.For example, the network communication unit 230 transmits information toanother node and receives information from the other node. For example,the other node includes another base station and a core network node.

(Storage Unit 240)

The storage unit 240 stores programs and data for operations of the basestation 200-2.

(Processing Unit 250)

The processing unit 250 provides various functions of the base station200-2. The processing unit 250 includes an information acquiring unit251 and a control unit 253. Alternatively, the processing unit 250 mayfurther include a component other than these components. That is, theprocessing unit 250 may also perform an operation other than operationsof these components.

(Information Acquiring Unit 251)

The information acquiring unit 251 acquires received power informationindicating received power of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in theterminal device 100-2.

For example, the terminal device 100-2 provides the received powerinformation to the base station 200-2. Then, the received powerinformation is stored in the storage unit 240. The information acquiringunit 251 acquires the received power information from the storage unit240 at any timing thereafter.

(a) First Received Power Information

The information acquiring unit 251 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-2.

The target base station is a base station serving as a target whosereceived quality will be calculated. That is, the target base station ischanged according to a base station whose received quality will becalculated. As an example, the processing unit 250 (for example, thecontrol unit 253) selects the target base station from among a pluralityof base stations that are positioned around the terminal device 100-2.

(b) Second Received Power Information

The information acquiring unit 251 acquires second received powerinformation indicating received power of a reference signal formeasurement transmitted by another base station using a weight set forbeamforming in the terminal device 100-2.

The other base station is a base station that is different from the basestation serving as a target whose received quality will be calculated.That is, the other base station may also be changed according to a basestation whose received quality will be calculated.

When the terminal device 100-2 wirelessly communicates with the targetbase station, the other base station serves as an interference source ofthe terminal device 100-2 and the target base station. Therefore, itshould be noted that the second received power information indicatesinterference power.

(Control Unit 253)

(a) Calculation of Received Quality

The control unit 253 calculates received quality of the reference signaltransmitted by the target base station in the terminal device 100-2based on the first received power information and the second receivedpower information.

(b) Handover

For example, the control unit 253 decides a handover of the terminaldevice 100-2 based on received quality information indicating thecalculated received quality.

Specifically, for example, the control unit 253 selects a base stationassociated with favorable received quality as a handover target basestation of the terminal device 100-2. Then, the control unit 253 decidesto handover the terminal device 100-2 to the selected base station.

(Others)

The base station 200-2 transmits, for example, a reference signal formeasurement using a weight set for beamforming. More specifically, forexample, the base station 200-2 (for example, the processing unit 250)maps a reference signal for measurement to radio resources andmultiplies the reference signal by a weight set.

<6.3. Method of Calculating Received Quality>

There is no difference in descriptions of the method of calculatingreceived quality between the first embodiment and the second embodimentexcept a difference in the main entity (that is, the terminal device100-1 is the main entity in the first embodiment and the base station200-2 is the main entity in the second embodiment). Therefore, redundantdescriptions will be omitted here. In the second embodiment,“information acquiring unit 143” is replaced by “information acquiringunit 251,” “control unit 145” is replaced by “control unit 253,” and“processing unit 140” is replaced by “processing unit 250.”

<6.4. Process Flow>

Next, an example of a process according to the second embodiment will bedescribed with reference to FIG. 15. FIG. 15 is a sequence diagramillustrating an example of a schematic flow of a process according tothe second embodiment.

The terminal device 100-2 (the measurement unit 141) measures receivedpower of a reference signal for measurement transmitted by a basestation using a weight set for beamforming in the terminal device 100-2(S321).

Then, the terminal device 100-2 (the control unit 155) provides receivedpower information indicating the received power to the base station200-2 (S323).

Then, the base station 200-2 performs a received quality calculatingprocess (S325). That is, the base station 200-2 (the informationacquiring unit 251) acquires first received power information indicatingreceived power of a reference signal for measurement transmitted by atarget base station using a weight set for beamforming in the terminaldevice 100-2. In addition, the base station 200-2 (the informationacquiring unit 251) acquires second received power informationindicating received power of a reference signal for measurementtransmitted by another base station using a weight set for beamformingin the terminal device 100-2. Then, the base station 200-2 (the controlunit 253) calculates received quality of the reference signaltransmitted by the target base station in the terminal device 100-2based on the first received power information and the second receivedpower information. Then, the process ends.

An example of a schematic flow of the received quality calculatingprocess is the same as the example of a schematic flow of a processaccording to the first embodiment described with reference to FIG. 12except for, for example, a difference in the main entities. In thesecond embodiment, “information acquiring unit 143” is replaced by“information acquiring unit 251” and “control unit 145” is replaced by“control unit 253.”

The second embodiment has been described above. Similarly to the firstembodiment, according to the second embodiment, it is possible to selecta cell that is more preferable for the terminal device 100-2 in anenvironment in which beamforming is performed.

In addition, in the second embodiment, the terminal device 100-2provides received power information to the base station 200-2, and thebase station 200-2 calculates the received quality based on the receivedpower information. Therefore, for example, the base station 200-2 canfreely calculate various types of received quality by combining receivedquality information.

7. Third Embodiment

Next, a third embodiment of the present disclosure will be describedwith reference to FIG. 16 and FIG. 17.

<7.1. Configuration of Terminal Device>

First, an example of a configuration of the terminal device 100-3according to the third embodiment will be described with reference toFIG. 16. FIG. 16 is a block diagram illustrating an example of aconfiguration of the terminal device 100-3 according to the thirdembodiment. As illustrated in FIG. 16, the terminal device 100-3includes an antenna unit 110, a wireless communication unit 120, astorage unit 130 and a processing unit 160.

There is no difference in descriptions of the antenna unit 110, thewireless communication unit 120, and the storage unit 130 between thefirst embodiment and the third embodiment except for different referencenumerals. Therefore, redundant descriptions will be omitted here, andonly the processing unit 160 will be described.

(Processing Unit 160)

The processing unit 160 provides various functions of the terminaldevice 100-3. The processing unit 160 includes a measurement unit 161,an information acquiring unit 163 and a control unit 165. The processingunit 160 may further include a component other than these components.That is, the processing unit 160 may also perform an operation otherthan operations of these components.

(Measurement Unit 161)

(a) Measurement of Received Power of Reference Signal Transmitted UsingWeight Set

The measurement unit 161 measures received power of a reference signalfor measurement transmitted by a base station using a weight set forbeamforming in the terminal device 100-3. For example, the measurementunit 161 outputs received power information indicating the receivedpower.

There is no difference in descriptions of measurement of the receivedpower between the first embodiment (the measurement unit 141) and thethird embodiment (the measurement unit 161). Therefore, redundantdescriptions will be omitted here.

(b) Measurement of Received Power of Signal Transmitted within ControlRegion Symbol

The measurement unit 161 measures received power of a signal transmittedwithin a symbol in which physical downlink control channels (PDCCHs) arearranged (hereinafter referred to as a “control region symbol”) in theterminal device 100-3. For example, the measurement unit 161 outputsreceived power information indicating the received power.

(b-1) Control Region Symbol

As an example, a subframe includes 14 symbols (for example, 14 OFDMAsymbols) and PDCCHs are arranged in the 1st to 3rd symbols. That is, the1st to 3rd symbols are each a control region symbol. In this case, themeasurement unit 161 measures received power of a signal transmittedwithin one or more control region symbols among the three control regionsymbols (that is, the 1st to 3rd symbols) in the terminal device 100-3.

As another example, a subframe includes 12 symbols (for example, 12OFDMA symbols) and PDCCHs may be arranged in the 1st and 2rd symbols.That is, the 1st and 2rd symbols may each be a control region symbol. Inthis case, the measurement unit 161 may measure received power of asignal transmitted within at least one control region symbol between thetwo control region symbols (that is, the 1st and 2rd symbols) in theterminal device 100-3.

As still another example, a subframe includes 6 symbols (for example, 6OFDMA symbols), and PDCCHs may be arranged in the 1st symbol. That is,the 1st symbol may be a control region symbol. In this case, themeasurement unit 161 may measure received power of a signal transmittedwithin the one control region symbol (that is, the 1st symbol) in theterminal device 100-3.

(b-2) Frequency Direction

As an example, the measurement unit 161 measures received power of asignal transmitted using radio resources across an entire frequency bandwithin the control region symbol in the terminal device 100-3. Morespecifically, for example, the measurement unit 161 measures receivedpower of a signal transmitted using resource elements across allcomponent carriers (CCs) within the control region symbol in theterminal device 100-3.

As another example, the measurement unit 161 may measure received powerof a signal transmitted using radio resources across some bands offrequency bands within the control region symbol in the terminal device100-3. More specifically, the measurement unit 161 may measure receivedpower of a signal transmitted using resource elements across some bandsof CCs within the control region symbol in the terminal device 100-3.

(b-3) Specific Process

As described above, the measurement unit 161 measures received power ofa signal transmitted within the control region symbol in the terminaldevice 100-3.

For example, the measurement unit 161 measures received power for eachpredetermined unit. More specifically, for example, the measurement unit141 calculates a total sum of received powers of signals transmittedwithin the control region symbols in the terminal device 100-3, dividesthe total sum by the number of predetermined units, and thus measuresreceived power for each predetermined unit.

As an example, the predetermined unit is a symbol. As another example,the predetermined unit may be a subframe or a resource block.

(Information Acquiring Unit 163)

(a) First Received Power Information

The information acquiring unit 163 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-3.

For example, the first received power information is output by themeasurement unit 161. The information acquiring unit 163 acquires thefirst received power information.

The target base station is a base station serving as a target whosereceived quality will be calculated. That is, the target base station ischanged according to a base station whose received quality will becalculated. As an example, the processing unit 160 (for example, thecontrol unit 165) selects the target base station from among a pluralityof base stations that are positioned around the terminal device 100-3.

(a) Second Received Power Information

The information acquiring unit 163 acquires second received powerinformation indicating received power of a signal transmitted within asymbol in which physical downlink control channels are arranged (thatis, a control region symbol) in the terminal device 100-3.

For example, the second received power information is output by themeasurement unit 161. The information acquiring unit 143 acquires thesecond received power information.

For example, in a symbol in which control channels are arranged (thatis, a control region symbol), no base station transmits a signal using aweight set for beamforming. Therefore, a signal transmitted in thesymbol is not significantly changed according to a weight set used by abase station. Therefore, it should be noted that the second receivedpower information indicates stable received power that is notsignificantly changed according to beamforming. The received powerincludes received power of a desired signal, interference and noise(S+I+N).

(Control Unit 165)

(a) Calculation of Received Quality

The control unit 165 calculates received quality of the reference signaltransmitted by the target base station in the terminal device 100-3based on the first received power information and the second receivedpower information. The method of calculating received quality will bedescribed below in detail.

(b) Provision to Base Station

For example, the control unit 165 provides the first received powerinformation to a base station 200-3.

For example, the control unit 165 provides received quality informationindicating the calculated received quality to the base station 200-3.

Specifically, for example, the control unit 165 provides the firstreceived power information and the received quality information to thebase station 200-3 periodically and/or according to a generation of apredetermined event. The control unit 165 provides the first receivedpower information and the received quality information to the basestation 200-3 through the antenna unit 110 and the wirelesscommunication unit 120.

<7.2. Method of Calculating Received Quality>

Next, an example of the method of calculating received quality in thethird embodiment will be described.

(Assumed Expression)

(a) Base Station

A base station is represented by “B.” Specifically, the target basestation is represented by “B(0).”

(b) Weight Set

A weight set is represented by “V” Specifically, an individual weightset is represented by “V(i)” (i=1, 2, 3, . . . ).

(c) Received Power of Reference Signal for Measurement

Received power of a reference signal for measurement in the terminaldevice 100-3 is represented by “RSRP.” There is no difference indescriptions of this point between the first embodiment and the secondembodiment. Therefore, redundant descriptions will be omitted here.

(d) Received Power of Signal Transmitted within Control Region Symbol

Received power of a signal transmitted within the control region symbol(that is, a symbol in which PDCCHs are arranged) in the terminal device100-3 is represented as follows.RSSI_(CONTROL)  [Math. 21](e) Received Quality of Reference Signal for Measurement

Received quality of a reference signal for measurement in the terminaldevice 100-3 is represented by “RSRQ.”

(e-1) First RS Transmission Case

For example, in the first RS transmission case, received quality of areference signal for measurement transmitted by a target base stationB(0) using a weight set V(i) in the terminal device 100-3 is representedas follows.RSRQ(B(0) with V(i))  [Math. 22]

Even in the first RS transmission case, similarly to the second RStransmission case, the terminal device 100-3 can calculate receivedquality.

(e-2) Second RS Transmission Case

For example, in the second RS transmission case, for example, receivedquality of a reference signal for measurement transmitted by a targetbase station B(0) using a weight set V in the terminal device 100-3 isrepresented as follows.RsRQ(B(0) with V)  [Math. 23](Received Quality in First RS Transmission Case)

First, in the first RS transmission case in which reference signals formeasurement multiplied by different weight sets are transmitted usingdifferent radio resources, an example of a method of calculatingreceived quality of a reference for measurement transmitted by thetarget base station B(0) using the weight set V(i) in the terminaldevice 100-3 will be described.

The control unit 165 calculates the received quality based on the firstreceived power information and the second received power information.

The first received power information indicates received power of areference signal for measurement transmitted by the target base stationB(0) using the weight set V(i) in a terminal device. As described above,the received power is represented as follows.RSRP(B(0) with V(i))  [Math. 24]

The second received power information indicates received power of asignal transmitted within the control region symbol (that is, a symbolin which PDCCHs are arranged) in the terminal device 100-3. As describedabove, the received power is represented as follows.RSSI_(CONTROL)  [Math. 25]

As an example, the control unit 165 calculates the received quality byperforming division using received power indicated by the first receivedpower information and received power indicated by the second receivedpower information.

Specifically, for example, the control unit 165 calculates the receivedquality as follows.

$\begin{matrix}{{{RSRQ}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu}{V(i)}} \right)}{{RSSI}_{CONTROL}}} & \left\lbrack {{Math}.\mspace{14mu} 26} \right\rbrack\end{matrix}$(Received Quality in Second RS Transmission Case)

Next, in the second RS transmission case in which reference signals formeasurement multiplied by different weight sets are transmitted usingthe same radio resources, an example of a method of calculating receivedquality of a reference for measurement transmitted by the target basestation B(0) using the weight set V in the terminal device 100-3 will bedescribed.

The control unit 165 calculates the received quality based on the firstreceived power information and the second received power information.

The first received power information indicates received power of areference signal for measurement transmitted by the target base stationB(0) using the weight set V in a terminal device. As described above,the received power is represented as follows.RSRP(B(0) with V)  [Math. 27]

The second received power information indicates received power of asignal transmitted within the control region symbol (that is, a symbolin which PDCCHs are arranged) in the terminal device 100-3. As describedabove, the received power is represented as follows.RSSI_(CONTROL)  [Math. 28]

As an example, the control unit 165 calculates the received quality byperforming division using received power indicated by the first receivedpower information and received power indicated by the second receivedpower information. Specifically, for example, the control unit 165calculates the received quality as follows.

$\begin{matrix}{{{RSRQ}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu} V} \right)} = \frac{{RSRP}\left( {{B(0)}\mspace{14mu}{with}\mspace{14mu} V} \right)}{{RSSI}_{CONTROL}}} & \left\lbrack {{Math}.\mspace{14mu} 29} \right\rbrack\end{matrix}$(Target Base Station)(a) Target Base Station

As described above, the target base station is a base station serving asa target whose received quality will be calculated. For example, theprocessing unit 160 (for example, the control unit 165) selects thetarget base station from among the plurality of base stations that arepositioned around the terminal device 100-3. As an example, theprocessing unit 160 selects a base station of a measurement target cell(for example, a serving cell and a neighbor cell) as the target basestation. As a result, received quality in the selected base station iscalculated.

It should be understood that not only one target base station but alsotwo or more target base stations may be selected. As a result, receivedquality in each of the two or more target base stations may becalculated.

(b) Weight Set Used by Target Base Station

As described above, in the first RS transmission case, the receivedquality can be calculated for each weight set used by the target basestation. For example, the processing unit 160 (for example, the controlunit 165) selects a weight set from among a plurality of weight setsused by the target base station. As a result, received quality for theselected weight set is calculated.

It should be understood that not only one weight set but also two ormore weight sets may be selected. As a result, received quality for eachof the two or more weight sets may be calculated.

<7.3. Process Flow>

Next, an example of a process according to the third embodiment will bedescribed with reference to FIG. 17. FIG. 17 is a flowchart illustratingan example of a schematic flow of a process according to the thirdembodiment. The process is performed by the terminal device 100-3.

The information acquiring unit 163 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-3 (S341).

In addition, the information acquiring unit 163 acquires second receivedpower information indicating received power of a signal transmittedwithin a symbol in which physical downlink control channels (PDCCHs) arearranged (that is, a control region symbol) in the terminal device 100-3(S343).

Then, the control unit 165 calculates received quality of the referencesignal transmitted by the target base station in the terminal device100-3 based on the first received power information and the secondreceived power information (S345). Then, the process ends.

The third embodiment has been described above. According to the thirdembodiment, for example, it is possible to select a cell that is morepreferable for the terminal device 100-3 in an environment in whichbeamforming is performed. More specifically, for example, receivedquality in the target base station is calculated based on received powerin the target base station (that is, received power indicated by firstreceived power information) and received power of a stable desiredsignal, interference and noise (S+I+N) (that is, received powerindicated by second received power information) in the environment inwhich beamforming is performed. Therefore, the received quality is notsignificantly changed according to a weight set used by a neighbor basestation of the target base station. Then, the received quality is usedwhen a handover or a cell selection/reselection is performed. As aresult, a cell that is more preferable for the terminal device 100-3 maybe selected.

In addition, in the third embodiment, since the terminal device 100-3calculates the received quality, information for calculating thereceived quality may not be transmitted to the base station 200-3.Therefore, radio resources may be saved.

8. Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be describedwith reference to FIG. 18 to FIG. 20.

While the terminal device 100-3 calculates received quality in the thirdembodiment, a base station 200-4 calculates received quality in thefourth embodiment.

<8.1. Configuration of Terminal Device>

First, an example of a configuration of the terminal device 100-4according to the fourth embodiment will be described with reference toFIG. 18. FIG. 18 is a block diagram illustrating an example of aconfiguration of the terminal device 100-4 according to the fourthembodiment. As illustrated in FIG. 18, the terminal device 100-4includes an antenna unit 110, a wireless communication unit 120, astorage unit 130 and a processing unit 170.

There is no difference in descriptions of the antenna unit 110, thewireless communication unit 120, and the storage unit 130 between thefirst embodiment and the fourth embodiment except for differentreference numerals. Therefore, redundant descriptions will be omittedhere, and only the processing unit 170 will be described.

(Processing Unit 170)

The processing unit 170 provides various functions of the terminaldevice 100-4. The processing unit 170 includes a measurement unit 161,an information acquiring unit 173 and a control unit 175. The processingunit 170 may further include a component other than these components.That is, the processing unit 170 may also perform an operation otherthan operations of these components.

There is no difference in descriptions of the measurement unit 161between the third embodiment and the fourth embodiment except fordifferent reference numerals. Therefore, redundant descriptions will beomitted here, and only the information acquiring unit 173 and thecontrol unit 175 will be described.

(Information Acquiring Unit 173)

(a) Received Power Information Indicating Received Power of ReferenceSignal for Measurement

The information acquiring unit 173 acquires received power informationindicating received power of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in theterminal device 100-4.

For example, the received power information is output by the measurementunit 161. The information acquiring unit 173 acquires the received powerinformation.

For example, the received power information is a candidate for firstreceived power information used for calculating received quality.

(b) Additional Received Power Information Indicating Received Power ofSignal Transmitted within Control Region Symbol.

The information acquiring unit 173 acquires additional received powerinformation indicating received power of a signal transmitted within asymbol in which physical downlink control channels (PDCCHs) are arranged(that is, a control region symbol) in the terminal device 100-4.

For example, the additional received power information is output by themeasurement unit 161. The information acquiring unit 173 acquires thereceived power information.

For example, the additional received power information is secondreceived power information that is used to calculate received quality.

(Control Unit 175)

The control unit 175 provides the received power information to the basestation 200-4. In addition, the control unit 175 further provides theadditional received power information to the base station 200-4.

Specifically, for example, the control unit 175 provides the receivedpower information and the additional received power information to thebase station 200-4 periodically and/or according to a generation of apredetermined event. The control unit 175 provides the received powerinformation and the additional received power information to the basestation 200-4 through the antenna unit 110 and the wirelesscommunication unit 120.

<8.2. Configuration of Base Station>

Next, an example of a configuration of the base station 200-4 accordingto the fourth embodiment will be described with reference to FIG. 19.FIG. 19 is a block diagram illustrating an example of a configuration ofthe base station 200-4 according to the fourth embodiment. Asillustrated in FIG. 19, the base station 200-4 includes the antenna unit210, the wireless communication unit 220, the network communication unit230, the storage unit 240 and a processing unit 260.

There is no difference in descriptions of the antenna unit 210, thewireless communication unit 220, the network communication unit 230 andthe storage unit 240 between the second embodiment and the fourthembodiment except for different reference numerals. Therefore, redundantdescriptions will be omitted here, and only the processing unit 260 willbe described.

(Information Acquiring Unit 261)

(a) First Received Power Information

The information acquiring unit 261 acquires first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100-4.

For example, the terminal device 100-4 provides received powerinformation indicating received power (that is, a candidate for thefirst received power information) of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in theterminal device 100-4 to the base station 200-4. Then, the receivedpower information is stored in the storage unit 240. The informationacquiring unit 261 acquires the first received power information (thatis, the received power information for the target base station) from thestorage unit 240 at any timing thereafter.

The target base station is a base station serving as a target whosereceived quality will be calculated. That is, the target base station ischanged according to a base station whose received quality will becalculated. As an example, the processing unit 260 (for example, acontrol unit 263) selects the target base station from among a pluralityof base stations that are positioned around the terminal device 100-4.

(b) Second Received Power Information

The information acquiring unit 261 acquires second received powerinformation indicating received power of a signal transmitted within asymbol in which physical downlink control channels are arranged (thatis, a control region symbol) in the terminal device 100-4.

For example, the terminal device 100-4 provides the second receivedpower information (that is, the additional received power information)to the base station 200-4. Then, the second received power informationis stored in the storage unit 240. The information acquiring unit 261acquires the second received power information from the storage unit 240at any timing thereafter.

(Control Unit 263)

(a) Calculation of Received Quality

The control unit 263 calculates received quality of the reference signaltransmitted by the target base station in the terminal device 100-4based on the first received power information and the second receivedpower information.

(b) Handover

For example, the control unit 263 decides to handover the terminaldevice 100-4 based on received quality information indicating thecalculated received quality.

Specifically, for example, the control unit 263 selects a base stationassociated with favorable received quality as a handover target basestation of the terminal device 100-4. Then, the control unit 263 decidesto handover the terminal device 100-4 to the selected base station.

(Others)

The base station 200-4 transmits, for example, a reference signal formeasurement using a weight set for beamforming. More specifically, forexample, the base station 200-4 (for example, the processing unit 260)maps a reference signal for measurement to radio resources andmultiplies the reference signal by a weight set.

<8.3. Method of Calculating Received Quality>

There is no difference in descriptions of the method of calculatingreceived quality between the third embodiment and the fourth embodimentexcept a difference in the main entities (that is, the terminal device100-3 is the main entity in the third embodiment and the base station200-4 is the main entity in the fourth embodiment). Therefore, redundantdescriptions will be omitted here. In the fourth embodiment,“information acquiring unit 163” is replaced by “information acquiringunit 261,” “control unit 165” is replaced by “control unit 263,” and“processing unit 160” is replaced by “processing unit 260.”

<8.4. Process Flow>

Next, an example of a process according to the fourth embodiment will bedescribed with reference to FIG. 20. FIG. 20 is a sequence diagramillustrating an example of a schematic flow of a process according tothe fourth embodiment.

The terminal device 100-4 (the measurement unit 161) measures receivedpower of a reference signal for measurement transmitted by a basestation using a weight set for beamforming in the terminal device 100-4(S361). In addition, the terminal device 100-4 (the measurement unit161) measures received power of a signal transmitted within a symbol inwhich physical downlink control channels (PDCCHs) are arranged (that is,a control region symbol) in the terminal device 100-4 (S361).

Then, the terminal device 100-4 (the control unit 175) provides receivedpower information indicating the received power of the reference signalin the terminal device 100-4 to the base station 200-4 (S363). Inaddition, the terminal device 100-4 (the control unit 175) furtherprovides additional received power information indicating the receivedpower of a signal transmitted within the control region symbol in theterminal device 100-4 to the base station 200-4 (S363).

Then, the base station 200-4 performs a received quality calculatingprocess (S365). That is, the base station 200-4 (the informationacquiring unit 261) acquires first received power information indicatingreceived power of a reference signal for measurement transmitted by atarget base station using a weight set for beamforming in the terminaldevice 100-4. In addition, the base station 200-4 (the informationacquiring unit 261) acquires second received power informationindicating received power of a signal transmitted within a symbol inwhich physical downlink control channels are arranged (that is, acontrol region symbol) in the terminal device 100-4. Then, the basestation 200-4 (the control unit 263) calculates received quality of thereference signal transmitted by the target base station in the terminaldevice 100-4 based on the first received power information and thesecond received power information. Then, the process ends.

An example of a schematic flow of the received quality calculatingprocess is the same as the example of a schematic flow of a processaccording to the third embodiment described with reference to FIG. 17except for, for example, a difference in the main entities. In thefourth embodiment, “information acquiring unit 163” is replaced by“information acquiring unit 261” and “control unit 165” is replaced by“control unit 263.”

The fourth embodiment has been described above. Similarly to the thirdembodiment, according to the fourth embodiment, it is possible to selecta cell that is more preferable for the terminal device 100-4 in anenvironment in which beamforming is performed.

In addition, according to the fourth embodiment, the terminal device100-4 provides received power information to the base station 200-4, andthe base station 200-4 calculates the received quality based on thereceived power information. Therefore, for example, the base station200-4 can freely calculate various types of received quality bycombining received quality information.

9. Application Examples

The technology according to the present disclosure is applicable to avariety of products. The base station 200 may also be implemented, forexample, as any type of evolved Node B (eNB) such as macro eNBs andsmall eNBs. Small eNBs may cover smaller cells than the macrocells ofpico eNBs, micro eNBs, or home (femt) eNBs. Instead, the base station200 may be implemented as another type of base station such as Nodes Bor base transceiver stations (BTSs). The base station 200 may includethe main apparatus (which is also referred to as base station apparatus)that controls wireless communication and one or more remote radio heads(RRHs) that are disposed at different locations from that of the mainapparatus. Further, various types of terminals as will be discussedlater may temporarily or semi-persistently execute the base stationfunction to operate as the base station 200. Further, at least part ofcomponents of the base station 200 may be implemented in a base stationdevice or a module for the base station device.

The terminal device 100 may be implemented as a mobile terminal such assmartphones, tablet personal computers (PCs), notebook PCs, portablegame terminals, portable/dongle mobile routers, and digital cameras, oran in-vehicle terminal such as car navigation apparatuses. The terminaldevice 100 may also be implemented as a terminal (which is also referredto as machine type communication (MTC) terminal) that performs machineto machine (M2M) communication.

Furthermore, at least part of components of the terminal device 100 maybe implemented as a module (e.g. integrated circuit module constitutedwith a single die) that is mounted on these terminals.

9.1. Application Examples for Base Station First Application Example

FIG. 21 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 and the base stationapparatus 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or a plurality of antennaelements (e.g. a plurality of antenna elements constituting a MIMOantenna) and is used for the base station apparatus 820 to transmit andreceive a wireless signal. The eNB 800 may include the plurality of theantennas 810 as illustrated in FIG. 21, and the plurality of antennas810 may, for example, correspond to a plurality of frequency bands usedby the eNB 800. It should be noted that while FIG. 21 illustrates anexample in which the eNB 800 includes the plurality of antennas 810, theeNB 800 may include the single antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of an upper layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data in asignal processed by the wireless communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may generate a bundled packet by bundling data from aplurality of base band processors to transfer the generated bundledpacket. The controller 821 may also have a logical function ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, and scheduling. The control maybe performed in cooperation with a surrounding eNB or a core network.The memory 822 includes a RAM and a ROM, and stores a program executedby the controller 821 and a variety of control data (such as, forexample, terminal list, transmission power data, and scheduling data).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to the core network 824. The controller821 may communicate with a core network node or another eNB via thenetwork interface 823. In this case, the controller 821 may be mutuallyconnected to the eNB 800 and a core network node or another eNB througha logical interface (e.g. S1 interface or X2 interface). The networkinterface 823 may be a wired communication interface or a wirelesscommunication interface for wireless backhaul. When the networkinterface 823 is a wireless communication interface, the networkinterface 823 may use a higher frequency band for wireless communicationthan a frequency band used by the wireless communication interface 825.

The wireless communication interface 825 supports a cellularcommunication system such as long term evolution (LTE) or LTE-Advanced,and provides wireless connection to a terminal located within the cellof the eNB 800 via the antenna 810. The wireless communication interface825 may typically include a base band (BB) processor 826 and an RFcircuit 827. The BB processor 826 may, for example, performencoding/decoding, modulation/demodulation, multiplexing/demultiplexing,and the like, and performs a variety of signal processing on each layer(e.g. L1, medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP)). The BB processor 826 may havepart or all of the logical functions as discussed above instead of thecontroller 821. The BB processor 826 may be a module including a memoryhaving a communication control program stored therein, a processor toexecute the program, and a related circuit, and the function of the BBprocessor 826 may be changeable by updating the program. The module maybe a card or blade to be inserted into a slot of the base stationapparatus 820, or a chip mounted on the card or the blade. Meanwhile,the RF circuit 827 may include a mixer, a filter, an amplifier, and thelike, and transmits and receives a wireless signal via the antenna 810.

The wireless communication interface 825 may include a plurality of theBB processors 826 as illustrated in FIG. 21, and the plurality of BBprocessors 826 may, for example, correspond to a plurality of frequencybands used by the eNB 800. The wireless communication interface 825 mayalso include a plurality of the RF circuits 827, as illustrated in FIG.21, and the plurality of RF circuits 827 may, for example, correspond toa plurality of antenna elements. FIG. 21 illustrates an example in whichthe wireless communication interface 825 includes the plurality of BBprocessors 826 and the plurality of RF circuits 827, but the wirelesscommunication interface 825 may include the single BB processor 826 orthe single RF circuit 827.

In the eNB 800 illustrated in FIG. 21, the information acquiring unit251 and the control unit 253 described above with reference to FIG. 14may be mounted in the wireless communication interface 825.Alternatively, at least some of the components may be mounted in thecontroller 821. As an example, the eNB 800 may be equipped with a moduleincluding some or all components of the wireless communication interface825 (for example, the BB processor 826) and/or the controller 821, andthe information acquiring unit 251 and the control unit 253 above may bemounted in the module. In this case, the module may store a programcausing the processor to function as the information acquiring unit 251and the control unit 253 above (that is, a program causing the processorto perform the operation of the information acquiring unit 251 and thecontrol unit 253 above) and execute the program. As another example, theprogram causing the processor to function as the information acquiringunit 251 and the control unit 253 above may be installed in the eNB 800,and the wireless communication interface 825 (for example, the BBprocessor 826) and/or the controller 821 may execute the program. Asdescribed above, the eNB 800, the base station apparatus 820, or themodule may be provided as an apparatus including the informationacquiring unit 251 and the control unit 253 above, and the programcausing the processor to function as the information acquiring unit 251and the control unit 253 above may be provided. A readable recordingmedium in which the program is recorded may be provided. For thesepoints, the information acquiring unit 261 and the control unit 263described above with reference to FIG. 19 are the same as theinformation acquiring unit 251 and the control unit 253.

In the eNB 800 illustrated in FIG. 21, the wireless communication unit220 described above with reference to FIG. 14 may be mounted in thewireless communication interface 825 (for example, the RF circuit 827).The antenna unit 210 may be mounted in the antenna 810. The networkcommunication unit 230 may be mounted in the controller 821 and/or thenetwork interface 823.

Second Application Example

FIG. 22 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station apparatus 850, and an RRH 860. Each of the antennas 840and the RRH 860 may be connected to each other via an RF cable. The basestation apparatus 850 and the RRH 860 may be connected to each other bya high speed line such as optical fiber cables.

Each of the antennas 840 includes a single or a plurality of antennaelements (e.g. antenna elements constituting a MIMO antenna), and isused for the RRH 860 to transmit and receive a wireless signal. The eNB830 may include a plurality of the antennas 840 as illustrated in FIG.22, and the plurality of antennas 840 may, for example, correspond to aplurality of frequency bands used by the eNB 830. FIG. 22 illustrates anexample in which the eNB 830 includes the plurality of antennas 840, butthe eNB 830 may include the single antenna 840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 21.

The wireless communication interface 855 supports a cellularcommunication system such as LTE and LTE-Advanced, and provides wirelessconnection to a terminal located in a sector corresponding to the RRH860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include a BB processor 856. The BB processor856 is the same as the BB processor 826 described with reference to FIG.21 except that the BB processor 856 is connected to an RF circuit 864 ofthe RRH 860 via the connection interface 857.

The wireless communication interface 855 may include a plurality of theBB processors 856, as illustrated in FIG. 22, and the plurality of BBprocessors 856 may, for example, correspond to a plurality of frequencybands used by the eNB 830 respectively. FIG. 22 illustrates an examplein which the wireless communication interface 855 includes the pluralityof BB processors 856, but the wireless communication interface 855 mayinclude the single BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may be a communication module forcommunication on the high speed line which connects the base stationapparatus 850 (wireless communication interface 855) to the RRH 860.

The RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station apparatus850. The connection interface 861 may be a communication module forcommunication on the high speed line.

The wireless communication interface 863 transmits and receives awireless signal via the antenna 840. The wireless communicationinterface 863 may typically include the RF circuit 864. The RF circuit864 may include a mixer, a filter, an amplifier and the like, andtransmits and receives a wireless signal via the antenna 840. Thewireless communication interface 863 may include a plurality of the RFcircuits 864 as illustrated in FIG. 22, and the plurality of RF circuits864 may, for example, correspond to a plurality of antenna elements.FIG. 22 illustrates an example in which the wireless communicationinterface 863 includes the plurality of RF circuits 864, but thewireless communication interface 863 may include the single RF circuit864.

In the eNB 830 illustrated in FIG. 22, the information acquiring unit251 and the control unit 253 described above with reference to FIG. 14may be mounted in the wireless communication interface 855 and/or thewireless communication interface 863. Alternatively, at least some ofthe components may be mounted in the controller 851. As an example, theeNB 830 may be equipped with a module including some or all componentsof the wireless communication interface 855 (for example, the BBprocessor 856) and/or the controller 851, and the information acquiringunit 251 and the control unit 253 above may be mounted in the module. Inthis case, the module may store a program causing the processor tofunction as the information acquiring unit 251 and the control unit 253above (that is, a program causing the processor to perform the operationof the information acquiring unit 251 and the control unit 253 above)and execute the program. As another example, the program causing theprocessor to function as the information acquiring unit 251 and thecontrol unit 253 above may be installed in the eNB 830, and the wirelesscommunication interface 855 (for example, the BB processor 856) and/orthe controller 851 may execute the program. As described above, the eNB830, the base station apparatus 850, or the module may be provided as anapparatus including the information acquiring unit 251 and the controlunit 253 above, and the program causing the processor to function as theinformation acquiring unit 251 and the control unit 253 above may beprovided. A readable recording medium in which the program is recordedmay be provided. For these points, the information acquiring unit 261and the control unit 263 described above with reference to FIG. 19 arethe same as the information acquiring unit 251 and the control unit 253.

In the eNB 830 illustrated in FIG. 22, the wireless communication unit220 described above with reference to FIG. 14 may be mounted in thewireless communication interface 863 (for example, the RF circuit 864).The antenna unit 210 may be mounted in the antenna 840. The networkcommunication unit 230 may be mounted in the controller 851 and/or thenetwork interface 853.

9.2. Application Examples for Terminal Device First Application Example

FIG. 23 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology according tothe present disclosure may be applied. The smartphone 900 includes aprocessor 901, a memory 902, a storage 903, an external connectioninterface 904, a camera 906, a sensor 907, a microphone 908, an inputdevice 909, a display device 910, a speaker 911, a wirelesscommunication interface 912, one or more antenna switches 915, one ormore antennas 916, a bus 917, a battery 918, and a secondary controller919.

The processor 901 may be, for example, a CPU or a system on chip (SoC),and controls the functions of an application layer and other layers ofthe smartphone 900. The memory 902 includes a RAM and a ROM, and storesa program executed by the processor 901 and data. The storage 903 mayinclude a storage medium such as semiconductor memories and hard disks.The external connection interface 904 is an interface for connecting thesmartphone 900 to an externally attached device such as memory cards anduniversal serial bus (USB) devices.

The camera 906 includes an image sensor such as charge coupled devices(CCDs) and complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 may include a sensor group including,for example, a positioning sensor, a gyro sensor, a geomagnetic sensor,and an acceleration sensor. The microphone 908 converts a sound that isinput into the smartphone 900 to an audio signal. The input device 909includes, for example, a touch sensor which detects that a screen of thedisplay device 910 is touched, a key pad, a keyboard, a button, or aswitch, and accepts an operation or an information input from a user.The display device 910 includes a screen such as liquid crystal displays(LCDs) and organic light emitting diode (OLED) displays, and displays anoutput image of the smartphone 900. The speaker 911 converts the audiosignal that is output from the smartphone 900 to a sound.

The wireless communication interface 912 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude the BB processor 913, the RF circuit 914, and the like. The BBprocessor 913 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 914 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 916. The wireless communicationinterface 912 may be a one-chip module in which the BB processor 913 andthe RF circuit 914 are integrated. The wireless communication interface912 may include a plurality of BB processors 913 and a plurality of RFcircuits 914 as illustrated in FIG. 23. FIG. 23 illustrates an examplein which the wireless communication interface 912 includes a pluralityof BB processors 913 and a plurality of RF circuits 914, but thewireless communication interface 912 may include a single BB processor913 or a single RF circuit 914.

Further, the wireless communication interface 912 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelesslocal area network (LAN) system in addition to the cellularcommunication system, and in this case, the wireless communicationinterface 912 may include the BB processor 913 and the RF circuit 914for each wireless communication system.

Each antenna switch 915 switches a connection destination of the antenna916 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 912.

Each of the antennas 916 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 912. The smartphone 900 may include aplurality of antennas 916 as illustrated in FIG. 23. FIG. 23 illustratesan example in which the smartphone 900 includes a plurality of antennas916, but the smartphone 900 may include a single antenna 916.

Further, the smartphone 900 may include the antenna 916 for eachwireless communication system. In this case, the antenna switch 915 maybe omitted from a configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the secondarycontroller 919 to each other. The battery 918 supplies electric power toeach block of the smartphone 900 illustrated in FIG. 23 via a feederline that is partially illustrated in the figure as a dashed line. Thesecondary controller 919, for example, operates a minimally necessaryfunction of the smartphone 900 in a sleep mode.

In the smartphone 900 illustrated in FIG. 23, one or more components(the measurement unit 141, the information acquiring unit 143 and/or thecontrol unit 145) included in the processing unit 140 described abovewith reference to FIG. 11 may be mounted in the wireless communicationinterface 912. Alternatively, at least some of the components may bemounted in the processor 901 or the secondary controller 919. As anexample, the smartphone 900 may be equipped with a module including someor all components of the wireless communication interface 912 (forexample, the BB processor 913), the processor 901, and/or the secondarycontroller 919, and the one or more components above may be mounted inthe module. In this case, the module may store a program causing theprocessor to function as the one or more components above (that is, aprogram causing the processor to perform the operation of the one ormore components above) and execute the program. As another example, theprogram causing the processor to function as the one or more componentsabove may be installed in the smartphone 900, and the wirelesscommunication interface 912 (for example, the BB processor 913), theprocessor 901, and/or the secondary controller 919 may execute theprogram. As described above, the smartphone 900 or the module may beprovided as an apparatus including the one or more components above, andthe program causing the processor to function as the one or morecomponents above may be provided. A readable recording medium in whichthe program is recorded may be provided. For these points, one or morecomponents (the measurement unit 141, the information acquiring unit 153and/or the control unit 155) included in the processing unit 150described with reference to FIG. 13, one or more components (themeasurement unit 161, the information acquiring unit 163 and/or thecontrol unit 165) included in the processing unit 160 described withreference to FIG. 16, and one or more components (the measurement unit161, the information acquiring unit 173 and/or the control unit 175)included in the processing unit 170 described with reference to FIG. 18are similar to the one or more components included in the processingunit 140.

In the smartphone 900 illustrated in FIG. 23, for example, the wirelesscommunication unit 120 described above with reference to FIG. 11 may bemounted in the wireless communication interface 912 (for example, the RFcircuit 914). The antenna unit 110 may be mounted in the antenna 916.

Second Application Example

FIG. 24 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied. The car navigationapparatus 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a wireless communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC, and controls thenavigation function and the other functions of the car navigationapparatus 920. The memory 922 includes a RAM and a ROM, and stores aprogram executed by the processor 921 and data.

The GPS module 924 uses a GPS signal received from a GPS satellite tomeasure the position (e.g. latitude, longitude, and altitude) of the carnavigation apparatus 920. The sensor 925 may include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, and an airpressure sensor. The data interface 926 is, for example, connected to anin-vehicle network 941 via a terminal that is not illustrated, andacquires data such as vehicle speed data generated on the vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g. CD or DVD) inserted into the storage medium interface 928. Theinput device 929 includes, for example, a touch sensor which detectsthat a screen of the display device 930 is touched, a button, or aswitch, and accepts operation or information input from a user. Thedisplay device 930 includes a screen such as LCDs and OLED displays, anddisplays an image of the navigation function or the reproduced content.The speaker 931 outputs a sound of the navigation function or thereproduced content.

The wireless communication interface 933 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude the BB processor 934, the RF circuit 935, and the like. The BBprocessor 934 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 935 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 937. The wireless communicationinterface 933 may be a one-chip module in which the BB processor 934 andthe RF circuit 935 are integrated. The wireless communication interface933 may include a plurality of BB processors 934 and a plurality of RFcircuits 935 as illustrated in FIG. 24. FIG. 24 illustrates an examplein which the wireless communication interface 933 includes a pluralityof BB processors 934 and a plurality of RF circuits 935, but thewireless communication interface 933 may be a single BB processor 934 ora single RF circuit 935.

Further, the wireless communication interface 933 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelessLAN system in addition to the cellular communication system, and in thiscase, the wireless communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each wireless communicationsystem.

Each antenna switch 936 switches a connection destination of the antenna937 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 933.

Each of the antennas 937 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 933. The car navigation apparatus 920includes a plurality of antennas 937 as illustrated in FIG. 24. FIG. 24illustrates an example in which the car navigation apparatus 920includes a plurality of antennas 937, but the car navigation apparatus920 may include a single antenna 937.

Further, the smartphone 920 may include the antenna 937 for eachwireless communication system. In this case, the antenna switch 936 maybe omitted from a configuration of the car navigation apparatus 920.

The battery 950 supplies electric power to each block of the carnavigation apparatus 930 illustrated in FIG. 21 via a feeder line thatis partially illustrated in the figure as a dashed line. The battery 950accumulates the electric power supplied from the vehicle.

In the car navigation apparatus 920 illustrated in FIG. 24, one or morecomponents (the measurement unit 141, the information acquiring unit 143and/or the control unit 145) included in the processing unit 140described above with reference to FIG. 11 may be mounted in the wirelesscommunication interface 933.

Alternatively, at least some of the components may be mounted in theprocessor 921. As an example, the car navigation apparatus 920 may beequipped with a module including some or all components of the wirelesscommunication interface 933 (for example, the BB processor 934), theprocessor 901, and/or the processor 921, and the one or more componentsabove may be mounted in the module. In this case, the module may store aprogram causing the processor to function as the one or more componentsabove (that is, a program causing the processor to perform the operationof the one or more components above) and execute the program. As anotherexample, the program causing the processor to function as the one ormore components above may be installed in the car navigation apparatus920, and the wireless communication interface 933 (for example, the BBprocessor 934), and/or the processor 921 may execute the program. Asdescribed above, the car navigation apparatus 920 or the module may beprovided as an apparatus including the one or more components above, andthe program causing the processor to function as the one or morecomponents above may be provided. A readable recording medium in whichthe program is recorded may be provided. For these points, one or morecomponents (the measurement unit 141, the information acquiring unit 153and/or the control unit 155) included in the processing unit 150described with reference to FIG. 13, one or more components (themeasurement unit 161, the information acquiring unit 163 and/or thecontrol unit 165) included in the processing unit 160 described withreference to FIG. 16, and one or more components (the measurement unit161, the information acquiring unit 173 and/or the control unit 175)included in the processing unit 170 described with reference to FIG. 18are similar to the one or more components included in the processingunit 140.

In the car navigation apparatus 920 illustrated in FIG. 24, for example,the wireless communication unit 120 described above with reference toFIG. 11 may be mounted in the wireless communication interface 933 (forexample, the RF circuit 935). The antenna unit 110 may be mounted in theantenna 937.

Further, the technique according to the present disclosure may beimplemented as an in-vehicle system (or a vehicle) 940 including one ormore blocks of the above-described car navigation apparatus 920, anin-vehicle network 941 and a vehicle side module 942. That is, thein-vehicle system (or the vehicle) 940 may be provided as an apparatusincluding one or more components included in the processing unit 140 (orthe processing unit 150, the processing unit 160, or the processing unit170). The vehicle side module 942 generates vehicle side data such asvehicle speed, engine speed and failure information and outputs thegenerated data to the in-vehicle network 961.

10. Conclusion

The device and the processes according to the embodiments of the presentdisclosure have been described so far with reference to FIG. 3 to FIG.24.

First Embodiment and Second Embodiment

According to the first embodiment and the second embodiment of thepresent disclosure, there is provided a device that includes aninformation acquiring unit configured to acquire first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100 and second received powerinformation indicating received power of a reference signal formeasurement transmitted by another base station using a weight set forbeamforming in the terminal device 100 and a control unit configured tocalculate received quality of the reference signal transmitted by thetarget base station in the terminal device 100 based on the firstreceived power information and the second received power information.

Accordingly, for example, it is possible to select a cell that is morepreferable for the terminal device 100 in an environment in whichbeamforming is performed.

More specifically, for example, received quality in the target basestation is calculated based on received power (that is, received powerindicated by first received power information) in the target basestation and interference (that is, received power indicated by secondreceived power information) in an environment in which beamforming isperformed. Therefore, the received quality may be close to receivedquality when the terminal device 100 performs wireless communication inthe environment in which beamforming is performed. Then, the receivedquality is used when a handover or a cell selection/reselection isperformed. As a result, a cell that is more preferable for the terminaldevice 100 may be selected.

In the first embodiment, the device is the terminal device 100 or amodule for the terminal device 100. In addition, in the secondembodiment, the device is the base station 200, a base station devicefor the base station 200, or a module for the base station device.

Third Embodiment and Fourth Embodiment

According to the third embodiment and the fourth embodiment of thepresent disclosure, there is provided a device that includes aninformation acquiring unit configured to acquire first received powerinformation indicating received power of a reference signal formeasurement transmitted by a target base station using a weight set forbeamforming in the terminal device 100 and second received powerinformation indicating received power of a signal transmitted within asymbol in which physical downlink control channels are arranged in theterminal device 100 and a control unit configured to calculate receivedquality of the reference signal transmitted by the target base stationin the terminal device 100 using the first received power informationand the second received power information.

Accordingly, for example, it is possible to select a cell that is morepreferable for the terminal device 100 in an environment in whichbeamforming is performed.

More specifically, for example, received quality in the target basestation is calculated based on received power in the target base station(that is, received power indicated by first received power information)and received power of a stable desired signal, interference and noise(S+I+N) (that is, received power indicated by second received powerinformation) in an environment in which beamforming is performed.Therefore, the received quality is not significantly changed accordingto a weight set used by a neighbor base station of the target basestation. Then, the received quality is used when a handover or a cellselection/reselection is performed. As a result, a cell that is morepreferable for the terminal device 100 may be selected.

In the third embodiment, the device is the terminal device 100 or amodule for the terminal device 100. In addition, in the fourthembodiment, the device is the base station 200, a base station devicefor the base station 200, or a module for the base station device.

The preferred embodiment of the present disclosure has been describedabove with reference to the accompanying drawings, whilst the presentdisclosure is not limited to the above examples. A person skilled in theart may find various alterations and modifications within the scope ofthe appended claims, and it should be understood that they willnaturally come under the technical scope of the present disclosure.

For example, while an example in which a communication system supports,for example, LTE, LTE-Advanced or a communication standard equivalentthereto has been described, the present disclosure is not limitedthereto. For example, the communication system may be a system thatsupports another communication standard.

Further, it is not always necessary to execute the processing steps inthe processing in the present specification in chronological order inorder described in the flowcharts or the sequence diagrams. For example,the processing steps in the above-described processing may be executedin order different from the order described in the flowcharts or thesequence diagrams or may be executed in parallel.

Further, it is also possible to create a computer program for making aprocessor (such as, for example, a CPU and a DSP) provided atapparatuses (such as, for example, the terminal device or the module forthe terminal device, or the base station, the base station device forthe base station or the module of the base station device) in thepresent specification function as components (for example, aninformation acquiring unit and the control unit) of the above-describedapparatuses (in other words, a computer program for making the processorexecute operation of the components of the above-described apparatuses).Further, it is also possible to provide a recording medium having theabove-described computer program recorded therein. Further, it is alsopossible to provide an apparatus (such as, for example, a finishedproduct and a module (such as parts, processing circuits and chips) forthe finished product) including a memory having the above-describedcomputer program stored therein and one or more processors which canexecute the above-described computer program. Further, a methodincluding the operation of the components (for example, an informationacquiring unit and the control unit) of the above-described apparatusesis included in the technique according to the present disclosure.

In addition, the effects described in the present specification aremerely illustrative and demonstrative, and not limitative. In otherwords, the technology according to the present disclosure can exhibitother effects that are evident to those skilled in the art along with orinstead of the effects based on the present specification.

Additionally, the present technology may also be configured as below.

(1)

A device including:

an acquiring unit configured to acquire first received power informationindicating received power of a reference signal for measurementtransmitted by a target base station using a weight set for beamformingin a terminal device and second received power information indicatingreceived power of a reference signal for measurement transmitted byanother base station using a weight set for beamforming in the terminaldevice; and

a control unit configured to calculate received quality of the referencesignal transmitted by the target base station in the terminal devicebased on the first received power information and the second receivedpower information.

(2)

The device according to (1),

wherein the acquiring unit acquires the second received powerinformation for each of a plurality of other base stations, and

the control unit calculates the received quality based on the firstreceived power information and the second received power information foreach of the plurality of other base stations.

(3)

The device according to (2),

wherein the control unit calculates the received quality based on firstreceived power indicated by the first received power information andsecond received power calculated based on the second received powerinformation for each of the plurality of other base stations.

(4)

The device according to any one of (1) to (3),

wherein the acquiring unit acquires the second received powerinformation of each of two or more weight sets, and

the control unit calculates the received quality based on the firstreceived power information and the second received power information ofeach of the two or more weight sets.

(5)

The device according to (4),

wherein the control unit calculates the received quality based on firstreceived power indicated by the first received power information andsecond received power calculated based on the second received powerinformation of each of the two or more weight sets.

(6)

The device according to any one of (1) to (5),

wherein the acquiring unit acquires the second received powerinformation of each of two or more weight sets for each of a pluralityof other base stations, and

the control unit calculates the received quality based on the firstreceived power information and the second received power information ofeach of the two or more weight sets for each of the plurality of otherbase stations.

(7)

The device according to (6),

wherein the control unit calculates the received quality based on firstreceived power indicated by the first received power information andsecond received power calculated based on the second received powerinformation of each of the two or more weight sets for each of theplurality of other base stations.

(8)

The device according to any one of (4) to (7),

wherein the two or more weight sets are weight sets that provide higherreceived power in the terminal device than other weight sets.

(9)

The device according to any one of (4) to (7),

wherein the two or more weight sets are designated weight sets.

(10)

The device according to (2) or (3),

wherein the weight set used by the other base station is a weight setthat provides higher received power in the terminal device than otherweight sets.

(11)

The device according to (2) or (3),

wherein the weight set used by the other base station is a designatedweight set.

(12)

The device according to (3), (5), or (7),

wherein the second received power is a sum of received powers indicatedby the second received power information.

(13)

The device according to (3), (5), (7), or (12),

wherein the control unit calculates the received quality by performingdivision using the first received power and the second received power.

(14)

A device including:

an acquiring unit configured to acquire first received power informationindicating received power of a reference signal for measurementtransmitted by a target base station using a weight set for beamformingin a terminal device and second received power information indicatingreceived power of a signal transmitted within a symbol in which physicaldownlink control channels are arranged in the terminal device; and

a control unit configured to calculate received quality of the referencesignal transmitted by the target base station in the terminal deviceusing the first received power information and the second received powerinformation.

(15)

The device according to (14),

wherein the control unit calculates the received quality by performingdivision using the received power indicated by the first received powerinformation and the received power indicated by the second receivedpower information.

(16)

A device including:

an acquiring unit configured to acquire received power informationindicating received power of a reference signal for measurementtransmitted by a base station using a weight set for beamforming in aterminal device; and

a control unit configured to provide the received power information to abase station.

(17)

The device according to (16),

wherein the acquiring unit acquires additional received powerinformation indicating received power of a signal transmitted within asymbol in which physical downlink control channels are arranged in theterminal device; and

the control unit further provides the additional received powerinformation to the base station.

(18)

The device according to any one of (1) to (17),

wherein the device is the terminal device or a module for the terminaldevice.

(19)

The device according to any one of (1) to (15),

wherein the device is a base station, a base station device for the basestation, or a module for the base station device.

(20)

The device according to any one of (1) to (19),

wherein the beamforming is large-scale MIMO beamforming.

(21)

A method including:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a referencesignal for measurement transmitted by another base station using aweight set for beamforming in the terminal device; and

calculating, by a processor, received quality of the reference signaltransmitted by the target base station in the terminal device based onthe first received power information and the second received powerinformation.

(22)

A program for causing a processor to execute:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a referencesignal for measurement transmitted by another base station using aweight set for beamforming in the terminal device; and

calculating received quality of the reference signal transmitted by thetarget base station in the terminal device based on the first receivedpower information and the second received power information.

(23)

A readable recording medium having a program recorded thereon, theprogram causing a processor to execute:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a referencesignal for measurement transmitted by another base station using aweight set for beamforming in the terminal device; and

calculating received quality of the reference signal transmitted by thetarget base station in the terminal device based on the first receivedpower information and the second received power information.

(24)

A method including:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a signaltransmitted within a symbol in which physical downlink control channelsare arranged in the terminal device; and

calculating, by a processor, received quality of the reference signaltransmitted by the target base station in the terminal device using thefirst received power information and the second received powerinformation.

(25)

A program for causing a processor to execute:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a signaltransmitted within a symbol in which physical downlink control channelsare arranged in the terminal device; and

calculating received quality of the reference signal transmitted by thetarget base station in the terminal device using the first receivedpower information and the second received power information.

(26)

A readable recording medium having a program recorded thereon, theprogram causing a processor to execute:

acquiring first received power information indicating received power ofa reference signal for measurement transmitted by a target base stationusing a weight set for beamforming in a terminal device and secondreceived power information indicating received power of a signaltransmitted within a symbol in which physical downlink control channelsare arranged in the terminal device; and

calculating received quality of the reference signal transmitted by thetarget base station in the terminal device using the first receivedpower information and the second received power information.

(27)

A method including:

acquiring received power information indicating received power of areference signal for measurement transmitted by a base station using aweight set for beamforming in a terminal device; and

providing, by a processor, the received power information to a basestation.

(28)

A program for causing a processor to execute:

acquiring received power information indicating received power of areference signal for measurement transmitted by a base station using aweight set for beamforming in a terminal device; and

providing the received power information to a base station.

(29)

A readable recording medium having a program recorded thereon, theprogram for causing a processor to execute:

acquiring received power information indicating received power of areference signal for measurement transmitted by a base station using aweight set for beamforming in a terminal device; and

providing the received power information to a base station.

REFERENCE SIGNS LIST

-   1 communication system-   30 subframe-   31 control area-   33 data area-   100 terminal device-   143, 153, 163, 173 information acquiring unit-   145, 155, 165, 175 control unit-   200 terminal device-   251, 261 information acquiring unit-   253, 263 control unit

The invention claimed is:
 1. A device, comprising: processing circuitry configured to: receive a first received power of a first reference signal, transmitted via first radio resources by a target base station, for measurement by a terminal device using a weight set for beamforming in the terminal device; receive a plurality of second received power of a second reference signal, transmitted via second radio resources by a plurality of other base stations, for another measurement by the terminal device, the second resources being different than the first resources; and calculate a received quality of the first reference signal based on the first received power and a sum of the plurality of the second received power.
 2. The device according to claim 1, wherein the processing circuitry receives the second received power of each of two or more weight sets, and the processing circuitry calculates the received quality based on each of the two or more weight sets.
 3. The device according to claim 2, wherein the two or more weight sets provide higher received power in the terminal device than other weight sets.
 4. The device according to claim 2, wherein the two or more weight sets are designated weight sets.
 5. The device according to claim 1, wherein a weight set, used by another base station, provides higher received power in the terminal device than other weight sets.
 6. The device according to claim 1, wherein the processing circuitry receives the second received power of each of two or more weight sets for each of the plurality of other base stations, and the processing circuitry calculates the received quality based on each of the two or more weight sets for each of the plurality of other base stations.
 7. The device according to claim 6, wherein the processing circuitry calculates the received quality based on the first received power, which is calculated based on first received power information.
 8. The device according to claim 1, wherein a weight set, used by another base station, is a designated weight set.
 9. The device according to claim 1, wherein the device is the terminal device or a module for the terminal device.
 10. The device according to claim 1, wherein the device is a base station, a base station device for the base station, or a module for the base station device.
 11. The device according to claim 1, wherein the beamforming is large-scale multiple input multiple output (MIMO) beamforming.
 12. The device according to claim 1, wherein the received quality is a received quality in the target base station when the target base station uses the first weight set for the beamforming in the terminal device.
 13. A device, comprising: processing circuitry configured to: receive a first received power of a first reference signal, transmitted via first radio resources by a target base station, for a measurement by a terminal device using a weight set for beamforming in the terminal device; receive a plurality of second received power of a signal, each transmitted within a corresponding symbol in which physical downlink control channels are arranged in the terminal device, the physical downlink control channels being different than the first resources; and calculate a received quality of the first reference signal by dividing the first received power by a sum of the plurality of the second received power.
 14. The device according to claim 13, wherein the received quality is a received quality in the target base station when the target base station uses the weight set for the beamforming in the terminal device.
 15. The device according to claim 13, wherein the device is the terminal device or a module for the terminal device.
 16. The device according to claim 13, wherein the beamforming is large-scale multiple input multiple output (MIMO) beamforming.
 17. The device according to claim 13, wherein the device is the terminal device or a module for the terminal device.
 18. A device, comprising: processing circuitry configured to: receive a first received power of a first reference signal, transmitted via first radio resources by a target base station, for a measurement by a terminal device using a weight set for beamforming in the terminal device; receive a plurality of second received power of a signal, each transmitted within a corresponding symbol in which physical downlink control channels are arranged in the terminal device; and provide the first received power and the plurality of the second received power to another device, the another device calculating a received quality based on the first received power and a sum of the plurality of the second received power. 